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diff --git a/scripts/fill_help_tables.sql b/scripts/fill_help_tables.sql index e110c00c277..d0efb750330 100644 --- a/scripts/fill_help_tables.sql +++ b/scripts/fill_help_tables.sql @@ -742,7 +742,7 @@ insert into help_topic (help_topic_id,help_category_id,name,description,example, insert into help_topic (help_topic_id,help_category_id,name,description,example,url) values (658,39,'CREATE SEQUENCE','CREATE SEQUENCE was introduced in MariaDB 10.3.\n \nSyntax\n------ \nCREATE [OR REPLACE] [TEMPORARY] SEQUENCE [IF NOT EXISTS]\nsequence_name\n[ INCREMENT [ BY | = ] increment ]\n[ MINVALUE [=] minvalue | NO MINVALUE | NOMINVALUE ]\n[ MAXVALUE [=] maxvalue | NO MAXVALUE | NOMAXVALUE ]\n[ START [ WITH | = ] start ] \n[ CACHE [=] cache | NOCACHE ] [ CYCLE | NOCYCLE] \n[table_options]\n \nThe options for CREATE SEQUENCE can be given in any order,\noptionally followed by table_options.\n \ntable_options can be any of the normal table options in\nCREATE TABLE but the most usable ones are ENGINE=... and\nCOMMENT=.\n \nNOMAXVALUE and NOMINVALUE are there to allow one to create\nSEQUENCEs using the Oracle syntax.\n \nDescription\n----------- \nCREATE SEQUENCE will create a sequence that generates new\nvalues when called with NEXT VALUE FOR sequence_name. It\'s\nan alternative to AUTO INCREMENT when one wants to have more\ncontrol of how the numbers are generated. As the SEQUENCE\ncaches values (up to CACHE) it can in some cases be much\nfaster than AUTO INCREMENT. Another benefit is that one can\naccess the last value generated by all used sequences, which\nsolves one of the limitations with LAST_INSERT_ID().\n \nCREATE SEQUENCE requires the CREATE privilege.\n \nDROP SEQUENCE can be used to drop a sequence, and ALTER\nSEQUENCE to change it.\n \nArguments to Create\n \nThe following options may be used:\n \nOption | Default value | Â Description | \n \nINCREMENT | Â 1 | Increment to use for values. May be\nnegative. Setting an increment of 0 causes the sequence to\nuse the value of the auto_increment_increment system\nvariable at the time of creation, which is always a positive\nnumber. (see MDEV-16035). | \n \nMINVALUE | 1 if INCREMENT > 0 and -9223372036854775807 if\nINCREMENT < 0 | Minimum value for the sequence | \n \nMAXVALUE | 9223372036854775806 if INCREMENT > 0 and -1 if\nINCREMENT < 0 | Max value for sequence | \n \nSTART | MINVALUE if INCREMENT > 0 and MAX_VALUE if\nINCREMENT< 0 | First value that the sequence will generate |\n\n \nCACHE | 1000 | Â Number of values that should be cached. 0\nif no CACHE. The underlying table will be updated first time\na new sequence number is generated and each time the cache\nruns out. | \n \nIf CYCLE is used then the sequence should start again from\nMINVALUE after it has run out of values. Default value is\nNOCYCLE.\n \nConstraints on Create Arguments\n \nTo be able to create a legal sequence, the following must\nhold:\nMAXVALUE >= start\nMAXVALUE > MINVALUE\nSTART >= MINVALUE\nMAXVALUE = -9223372036854775807 (LONGLONG_MIN+1)\n \nNote that sequences can\'t generate the maximum/minimum 64\nbit number because of the constraint of\nMINVALUE and MAXVALUE. \n \nExamples\n-------- \nCREATE SEQUENCE s START WITH 100 INCREMENT BY 10;\n \nCREATE SEQUENCE s2 START WITH -100 INCREMENT BY -10;\n \nThe following statement fails, as the increment conflicts\nwith the defaults\n \nCREATE SEQUENCE s3 START WITH -100 INCREMENT BY 10;\n \nERROR 4082 (HY000): Sequence \'test.s3\' values are\nconflicting\n \nThe sequence can be created by specifying workable minimum\nand maximum values:\n \nCREATE SEQUENCE s3 START WITH -100 INCREMENT BY 10\nMINVALUE=-100 MAXVALUE=1000;\n \n\n\nURL: https://mariadb.com/kb/en/library/create-sequence/','','https://mariadb.com/kb/en/library/create-sequence/'); insert into help_topic (help_topic_id,help_category_id,name,description,example,url) values (659,39,'CREATE SERVER','Syntax\n------ \nCREATE [OR REPLACE] SERVER [IF NOT EXISTS] server_name\n FOREIGN DATA WRAPPER wrapper_name\n OPTIONS (option [, option] ...)\n \noption:\n { HOST character-literal\n | DATABASE character-literal\n | USER character-literal\n | PASSWORD character-literal\n | SOCKET character-literal\n | OWNER character-literal\n | PORT numeric-literal }\n \nDescription\n----------- \nThis statement creates the definition of a server for use\nwith the Spider,\nFEDERATED or FederatedX storage\nengine. The CREATE SERVER statement creates a new row within\nthe\nservers table within the mysql database. This statement\nrequires the SUPER privilege.\n \nThe server_name should be a unique reference to the server.\nServer definitions\nare global within the scope of the server, it is not\npossible to qualify the\nserver definition to a specific database. server_name has a\nmaximum length of\n64 characters (names longer than 64 characters are silently\ntruncated), and is\ncase insensitive. You may specify the name as a quoted\nstring.\n \nThe wrapper_name should be mysql, and may be quoted with\nsingle quotes.\nOther values for wrapper_name are not currently supported.\n \nFor each option you must specify either a character literal\nor numeric literal.\nCharacter literals are UTF-8, support a maximum length of 64\ncharacters and\ndefault to a blank (empty) string. String literals are\nsilently truncated to 64\ncharacters. Numeric literals must be a number between 0 and\n9999, default value\nis 0.\n \nNote: The OWNER option is currently not applied, and has no\neffect on\nthe ownership or operation of the server connection that is\ncreated.\n \nThe CREATE SERVER statement creates an entry in the\nmysql.servers table that can later be used with the\nCREATE TABLE statement when creating a Spider, FederatedX or\nFEDERATED table. The options that you specify will\nbe used to populate the columns in the mysql.servers table.\nThe table columns\nare Server_name, Host, Db, Username, Password, Port and\nSocket.\n \n DROP SERVER removes a previously created server definition.\n\n \nCREATE SERVER is not written to the binary log, irrespective\nof\nthe binary log format being used.\n \nFor valid identifiers to use as server names, see Identifier\nNames.\n \nOR REPLACE\n \nIf the optional OR REPLACE clause is used, it acts as a\nshortcut for:\n \nDROP SERVER IF EXISTS name;\n \nCREATE SERVER server_name ...;\n \nIF NOT EXISTS\n \nIf the IF NOT EXISTS clause is used, MariaDB will return a\nwarning instead of an error if the server already exists.\nCannot be used together with OR REPLACE.\n \nExamples\n-------- \nCREATE SERVER s\nFOREIGN DATA WRAPPER mysql\nOPTIONS (USER \'Remote\', HOST \'192.168.1.106\', DATABASE\n\'test\');\n \nOR REPLACE and IF NOT EXISTS:\n \nCREATE SERVER s \nFOREIGN DATA WRAPPER mysql \nOPTIONS (USER \'Remote\', HOST \'192.168.1.106\', DATABASE\n\'test\');\nERROR 1476 (HY000): The foreign server, s, you are trying to\ncreate already exists\n \nCREATE OR REPLACE SERVER s \nFOREIGN DATA WRAPPER mysql \nOPTIONS (USER \'Remote\', HOST \'192.168.1.106\', DATABASE\n\'test\');\nQuery OK, 0 rows affected (0.00 sec)\n \nCREATE SERVER IF NOT EXISTS s \nFOREIGN DATA WRAPPER mysql \nOPTIONS (USER \'Remote\', HOST \'192.168.1.106\', DATABASE\n\'test\');\nQuery OK, 0 rows affected, 1 warning (0.00 sec)\n \nSHOW WARNINGS;\n \n+-------+------+----------------------------------------------------------------+\n| Level | Code | Message |\n+-------+------+----------------------------------------------------------------+\n| Note | 1476 | The foreign server, s, you are trying to\ncreate already exists |\n+-------+------+----------------------------------------------------------------+\n \n\n\nURL: https://mariadb.com/kb/en/library/create-server/','','https://mariadb.com/kb/en/library/create-server/'); insert into help_topic (help_topic_id,help_category_id,name,description,example,url) values (660,39,'CREATE TABLE','Syntax\n------ \nCREATE [OR REPLACE] [TEMPORARY] TABLE [IF NOT EXISTS]\ntbl_name\n (create_definition,...) [table_options ]...\n[partition_options]\nCREATE [OR REPLACE] [TEMPORARY] TABLE [IF NOT EXISTS]\ntbl_name\n [(create_definition,...)] [table_options ]...\n[partition_options]\n select_statement\nCREATE [OR REPLACE] [TEMPORARY] TABLE [IF NOT EXISTS]\ntbl_name\n { LIKE old_table_name | (LIKE old_table_name) }\n \nselect_statement:\n [IGNORE | REPLACE] [AS] SELECT ... (Some legal select\nstatement)\n \nDescription\n----------- \nUse the CREATE TABLE statement to create a table with the\ngiven name.\n \nIn its most basic form, the CREATE TABLE statement provides\na table name\nfollowed by a list of columns, indexes, and constraints. By\ndefault, the table\nis created in the default database. Specify a database with\ndb_name.tbl_name.\nIf you quote the table name, you must quote the database\nname and table name\nseparately as `db_name`.`tbl_name`. This is particularly\nuseful for CREATE TABLE ... SELECT, because it allows to\ncreate a table into a database, which contains data from\nother databases. See Identifier Qualifiers.\n \nIf a table with the same name exists, error 1050 results.\nUse IF NOT EXISTS\nto suppress this error and issue a note instead. Use SHOW\nWARNINGS\nto see notes.\n \nThe CREATE TABLE statement automatically commits the current\ntransaction,\nexcept when using the TEMPORARY keyword.\n \nFor valid identifiers to use as table names, see Identifier\nNames.\n \nNote: if the default_storage_engine is set to ColumnStore\nthen it needs setting on all UMs. Otherwise when the tables\nusing the default engine are replicated across UMs they will\nuse the wrong engine. You should therefore not use this\noption as a session variable with ColumnStore.\n \nMicrosecond precision can be between 0-6. If no precision is\nspecified it is assumed to be 0, for backward compatibility\nreasons.\n \nPrivileges\n \nExecuting the CREATE TABLE statement requires the CREATE\nprivilege for the table or the database.\n \nCREATE OR REPLACE TABLE ...\n \nThe OR REPLACE clause was added in MariaDB 10.0.8.\n \nIf the OR REPLACE clause is used and if the table already\nexists, then instead of returning an error, the server will\ndrop the existing table and replace it with the newly\ndefined table.\n \nThis syntax was originally added to make replication more\nrobust if it has to rollback and repeat statements such as\nCREATE ... SELECT on slaves.\n \nCREATE OR REPLACE TABLE table_name (a int);\n \nis basically the same as:\n \nDROP TABLE IF EXISTS table_name;\nCREATE TABLE table_name (a int);\n \nwith the following exceptions:\nIf table_name was locked with LOCK TABLES it will continue\nto be locked after the statement.\nTemporary tables are only dropped if the TEMPORARY keyword\nwas used. (With DROP TABLE, temporary tables are preferred\nto be dropped before normal tables).\n \nThings to be Aware of With CREATE OR REPLACE\n \nThe table is dropped first (if it existed), after that the\nCREATE is done. Because of this, if the CREATE fails, then\nthe table will not exist anymore after the statement. If the\ntable was used with LOCK TABLES it will be unlocked.\nOne can\'t use OR REPLACE together with IF EXISTS.\nSlaves in replication will by default use CREATE OR REPLACE\nwhen replicating CREATE statements that don\'\'t use IF\nEXISTS. This can be changed by setting the variable\nslave-ddl-exec-mode to STRICT.\n \nCREATE TABLE IF NOT EXISTS ...\n \nIf the IF NOT EXISTS clause is used, then the index will\nonly be created if an index with the same name does not\nalready exist. If the index already exists, then a warning\nwill be triggered by default.\n \nCREATE TEMPORARY TABLE ...\n \nUse the TEMPORARY keyword to create a temporary table that\nis only available to your current session. Temporary tables\nare dropped when the your session ends. Temporary table\nnames are specific to your session. They will not conflict\nwith other temporary tables from other session even if they\nshare the same name. They will shadow names of non-temporary\ntables or views, if they are identical. A temporary table\ncan have the same name as a non-temporary table which is\nlocated in the same database. In that case, their name will\nreference the temporary table when used in SQL statements.\nYou must have the CREATE TEMPORARY TABLES privilege on the\ndatabase to create temporary tables. If no storage engine is\nspecified, the default_tmp_storage_engine setting will\ndetermine the engine.\n \nCREATE TABLE ... LIKE\n \nUse the LIKE clause instead of a full table definition to\ncreate a table with the same definition as another table,\nincluding columns, indexes, and table options. Foreign key\ndefinitions, as well as any DATA DIRECTORY or INDEX\nDIRECTORY table options specified on the original table,\nwill not be created.\n \nCREATE TABLE ... SELECT\n \nYou can create a table containing data from other tables\nusing the CREATE ... SELECT statement. Columns will be\ncreated in the table for each field returned by the SELECT\nquery.\n \nYou can also define some columns normally and add other\ncolumns from a SELECT. You can also create columns in the\nnormal way and assign them some values using the query, this\nis done to force a certain type or other field\ncharacteristics. The columns that are not named in the query\nwill be placed before the others. For example:\n \nCREATE TABLE test (a INT NOT NULL, b CHAR(10)) ENGINE=MyISAM\n SELECT 5 AS b, c, d FROM another_table;\n \nRemember that the query just returns data. If you want to\nuse the same indexes, or the same columns attributes ([NOT]\nNULL, DEFAULT, AUTO_INCREMENT) in the new table, you need to\nspecify them manually. Types and sizes are not automatically\npreserved if no data returned by the SELECT requires the\nfull size, and VARCHAR could be converted into CHAR. The\nCAST() function can be used to forcee the new table to use\ncertain types.\n \nAliases (AS) are taken into account, and they should always\nbe used when you SELECT an expression (function,\narithmetical operation, etc).\n \nIf an error occurs during the query, the table will not be\ncreated at all.\n \nIf the new table has a primary key or UNIQUE indexes, you\ncan use the IGNORE or REPLACE keywords to handle duplicate\nkey errors during the query. IGNORE means that the newer\nvalues must not be inserted an identical value exists in the\nindex. REPLACE means that older values must be overwritten.\n \nIf the columns in the new table are more than the rows\nreturned by the query, the columns populated by the query\nwill be placed after other columns. Note that if the strict\nSQL_MODE is on, and the columns that are not names in the\nquery do not have a DEFAULT value, an error will raise and\nno rows will be copied.\n \nConcurrent inserts are not used during the execution of a\nCREATE ... SELECT.\n \nIf the table already exists, an error similar to the\nfollowing will be returned:\n \nERROR 1050 (42S01): Table \'t\' already exists\n \nIf the IF NOT EXISTS clause is used and the table exists, a\nnote will be produced instead of an error.\n \nTo insert rows from a query into an existing table, INSERT\n... SELECT can be used.\n \nColumn Definitions\n \ncreate_definition:\n { col_name column_definition | index_definition |\nperiod_definition | CHECK (expr) }\n \ncolumn_definition:\n data_type\n [NOT NULL | NULL] [DEFAULT default_value | (expression)]\n [AUTO_INCREMENT] [ZEROFILL] [UNIQUE [KEY] | [PRIMARY] KEY]\n [INVISIBLE] [{WITH|WITHOUT} SYSTEM VERSIONING]\n [COMMENT \'string\']\n [COLUMN_FORMAT {FIXED|DYNAMIC|DEFAULT}]\n [reference_definition]\n | data_type [GENERATED ALWAYS] AS { { ROW {START|END} } | {\n(expression) [VIRTUAL | PERSISTENT | STORED] } }\n [UNIQUE [KEY]] [COMMENT \'string\']\n \nconstraint_definition:\n CONSTRAINT [constraint_name] CHECK (expression)\nNote: MariaDB accepts the REFERENCES clause in ALTER TABLE\nand CREATE TABLE column definitions, but that syntax does\nnothing. MariaDB simply parses it without returning any\nerror or warning, for compatibility with other DBMS\'s.\nBefore MariaDB 10.2.1 this was also true for CHECK\nconstraints. Only the syntax for indexes described below\ncreates foreign keys.\n \nEach definition either creates a column in the table or\nspecifies and index or\nconstraint on one or more columns. See Indexes below for\ndetails\non creating indexes.\n \nCreate a column by specifying a column name and a data type,\noptionally\nfollowed by column options. See Data Types for a full list\nof data types allowed in MariaDB.\n \nNULL and NOT NULL\n \nUse the NULL or NOT NULL options to specify that values in\nthe column\nmay or may not be NULL, respectively. By default, values may\nbe NULL. See also NULL Values in MariaDB.\n \nDEFAULT Column Option\n \nThe DEFAULT clause was enhanced in MariaDB 10.2.1. Some\nenhancements include\nBLOB and TEXT columns now support DEFAULT.\nThe DEFAULT clause can now be used with an expression or\nfunction.\n \nSpecify a default value using the DEFAULT clause. If you\ndon\'t specify DEFAULT then the following rules apply:\nIf the column is not defined with NOT NULL, AUTO_INCREMENT\nor TIMESTAMP, an explicit DEFAULT NULL will be added.\nNote that in MySQL and in MariaDB before 10.1.6, you may get\nan explicit DEFAULT for primary key parts, if not specified\nwith NOT NULL.\n \nThe default value will be used if you INSERT a row without\nspecifying a value for that column, or if you specify\nDEFAULT for that column.\nBefore MariaDB 10.2.1 you couldn\'t usually provide an\nexpression or function to evaluate at\ninsertion time. You had to provide a constant default value\ninstead. The one\nexception is that you may use CURRENT_TIMESTAMP as\nthe default value for a TIMESTAMP column to use the current\ntimestamp at insertion time.\n \nCURRENT_TIMESTAMP may also be used as\nthe default value for a DATETIME\n \nFrom MariaDB 10.2.1 you can use most functions in DEFAULT.\nExpressions should have parentheses around them. If you use\na non deterministic function in DEFAULT then all inserts to\nthe table will be replicated in row mode. You can even refer\nto earlier columns in the DEFAULT expression:\n \nCREATE TABLE t1 (a int DEFAULT (1+1), b int DEFAULT (a+1));\nCREATE TABLE t2 (a bigint primary key DEFAULT UUID_SHORT());\n \nThe DEFAULT clause cannot contain any stored functions or\nsubqueries, and a column used in the clause must already\nhave been defined earlier in the statement.\n \nSince MariaDB 10.2.1, it is possible to assign BLOB or TEXT\ncolumns a DEFAULT value. In earlier versions, assigning a\ndefault to these columns was not possible.\n \nStarting from 10.3.3 you can also use DEFAULT (NEXT VALUE\nFOR sequence)\n \nAUTO_INCREMENT Column Option\n \nUse AUTO_INCREMENT to create a column whose value can\ncan be set automatically from a simple counter. You can only\nuse AUTO_INCREMENT\non a column with an integer type. The column must be a key,\nand there can only be\none AUTO_INCREMENT column in a table. If you insert a row\nwithout specifying\na value for that column (or if you specify 0, NULL, or\nDEFAULT\nas the value), the actual value will be taken from the\ncounter, with each insertion\nincrementing the counter by one. You can still insert a\nvalue explicitly. If you\ninsert a value that is greater than the current counter\nvalue, the counter is\nset based on the new value. An AUTO_INCREMENT column is\nimplicitly NOT NULL.\nUse LAST_INSERT_ID to get the AUTO_INCREMENT value\nmost recently used by an INSERT statement.\n \nZEROFILL Column Option\n \nIf the ZEROFILL column option is specified for a column\nusing a numeric data type, then the column will be set to\nUNSIGNED and the spaces used by default to pad the field are\nreplaced with zeros. ZEROFILL is ignored in expressions or\nas part of a UNION. ZEROFILL is a non-standard MySQL and\nMariaDB enhancement.\n \nPRIMARY KEY Column Option\n \nUse PRIMARY KEY (or just KEY) to make a column a primary\nkey. A primary key is a special type of a unique key. There\ncan be at most one primary key per table, and it is\nimplicitly NOT NULL.\n \nSpecifying a column as a unique key creates a unique index\non that column. See the Index Definitions section below for\nmore information.\n \nUNIQUE KEY Column Option\n \nUse UNIQUE KEY (or just UNIQUE) to specify that all values\nin the column\nmust be distinct from each other. Unless the column is NOT\nNULL, there may be\nmultiple rows with NULL in the column. \n \nSpecifying a column as a unique key creates a unique index\non that column. See the Index Definitions section below for\nmore information.\n \nCOMMENT Column Option\n \nYou can provide a comment for each column using the COMMENT\nclause. The maximum length is 1024 characters (it was 255\ncharacters before MariaDB 5.5). Use\nthe SHOW FULL COLUMNS statement to see column comments.\n \nGenerated Columns\n \nA generated column is a column in a table that cannot\nexplicitly be set to a specific value in a DML query.\nInstead, its value is automatically generated based on an\nexpression. This expression might generate the value based\non the values of other columns in the table, or it might\ngenerate the value by calling built-in functions or\nuser-defined functions (UDFs).\n \nThere are two types of generated columns:\nPERSISTENT or STORED: This type\'s value is actually stored\nin the table.\nVIRTUAL: This type\'s value is not stored at all. Instead,\nthe value is generated dynamically when the table is\nqueried. This type is the default.\n \nGenerated columns are also sometimes called computed columns\nor virtual columns.\n \nFor a complete description about generated columns and their\nlimitations, see Generated (Virtual and Persistent/Stored)\nColumns.\n \nCOLUMN_FORMAT\n \nCOLUMN_FORMAT is only used by MySQL Cluster, and is silently\nignored in MariaDB.\n \nCOMPRESSED\n \nCertain columns may be compressed. See Storage-Engine\nIndependent Column Compression.\n \nINVISIBLE\n \nColumns may be made invisible, and hidden in certain\ncontexts. See Invisible Columns.\n \nWITH SYSTEM VERSIONING Column Option\n \nColumns may be explicitly marked as included from system\nversioning. See System-versioned tables for details.\n \nWITHOUT SYSTEM VERSIONING Column Option\n \nColumns may be explicitly marked as excluded from system\nversioning. See System-versioned tables for details.\n \nIndex Definitions\n \nindex_definition:\n {INDEX|KEY} [index_name] [index_type] (index_col_name,...)\n[index_option] ...\n | {FULLTEXT|SPATIAL} [INDEX|KEY] [index_name]\n(index_col_name,...) [index_option] ...\n | [CONSTRAINT [symbol]] PRIMARY KEY [index_type]\n(index_col_name,...) [index_option] ...\n | [CONSTRAINT [symbol]] UNIQUE [INDEX|KEY] [index_name]\n[index_type] (index_col_name,...) [index_option] ...\n | [CONSTRAINT [symbol]] FOREIGN KEY [index_name]\n(index_col_name,...) reference_definition\n \nindex_col_name:\n col_name [(length)] [ASC | DESC]\n \nindex_type:\n USING {BTREE | HASH | RTREE}\n \nindex_option:\n KEY_BLOCK_SIZE [=] value\n | index_type\n | WITH PARSER parser_name\n | COMMENT \'string\'\n | CLUSTERING={YES| NO}\n \nreference_definition:\n REFERENCES tbl_name (index_col_name,...)\n [MATCH FULL | MATCH PARTIAL | MATCH SIMPLE]\n [ON DELETE reference_option]\n [ON UPDATE reference_option]\n \nreference_option:\n RESTRICT | CASCADE | SET NULL | NO ACTION\nINDEX and KEY are synonyms. \n \nIndex names are optional, if not specified an automatic name\nwill be assigned. Index name are needed to drop indexes and\nappear in error messages when a constraint is violated.\n \nIndex Categories\n \nPlain Indexes\n \nPlain indexes are regular indexes that are not unique, and\nare not acting as a primary key or a foreign key. They are\nalso not the \"specialized\" FULLTEXT or SPATIAL indexes.\n \nSee Getting Started with Indexes: Plain Indexes for more\ninformation.\n \nPRIMARY KEY\n \nFor PRIMARY KEY indexes, you can specify a name for the\nindex, but it is silently ignored, and the name of the index\nis always PRIMARY.\n \nSee Getting Started with Indexes: Primary Key for more\ninformation.\n \nUNIQUE\n \nThe UNIQUE keyword means that the index will not accept\nduplicated values, except for NULLs. An error will raise if\nyou try to insert duplicate values in a UNIQUE index.\n \nFor UNIQUE indexes, you can specify a name for the\nconstraint, using the CONSTRAINT keyword. That name will be\nused in error messages.\n \nSee Getting Started with Indexes: Unique Index for more\ninformation.\n \nFOREIGN KEY\n \nFor FOREIGN KEY indexes, a reference definition must be\nprovided.\n \nFor FOREIGN KEY indexes, you can specify a name for the\nconstraint, using the CONSTRAINT keyword. That name will be\nused in error messages.\n \nFirst, you have to specify the name of the target (parent)\ntable and a column or a column list which must be indexed\nand whose values must match to the foreign key\'s values.\nThe MATCH clause is accepted to improve the compatibility\nwith other DBMS\'s, but has no meaning in MariaDB. The ON\nDELETE and ON UPDATE clauses specify what must be done when\na DELETE (or a REPLACE) statements attempts to delete a\nreferenced row from the parent table, and when an UPDATE\nstatement attempts to modify the referenced foreign key\ncolumns in a parent table row, respectively. The following\noptions are allowed:\nRESTRICT: The delete/update operation is not performed. The\nstatement terminates with a 1451 error (SQLSTATE \'2300\').\nNO ACTION: Synonym for RESTRICT.\nCASCADE: The delete/update operation is performed in both\ntables.\nSET NULL: The update or delete goes ahead in the parent\ntable, and the corresponding foreign key fields in the child\ntable are set to NULL. (They must not be defined as NOT NULL\nfor this to succeed).\nSET DEFAULT: This option is currently implemented only for\nthe PBXT storage engine, which is disabled by default and no\nlonger maintained. It sets the child table\'s foreign key\nfields to their DEFAULT values when the referenced parent\ntable key entries are updated or deleted.\n \nIf either clause is omitted, the default behavior for the\nomitted clause is RESTRICT.\n \nSee Foreign Keys for more information.\n \nFULLTEXT\n \nUse the FULLTEXT keyword to create full-text indexes.\n \nSee Full-Text Indexes for more information.\n \nSPATIAL\n \nUse the SPATIAL keyword to create geometric indexes.\n \nSee SPATIAL INDEX for more information.\n \nIndex Options\n \nKEY_BLOCK_SIZE Index Option\n \nThe KEY_BLOCK_SIZE index option is similar to the\nKEY_BLOCK_SIZE table option.\n \nWith the InnoDB storage engine, if you specify a non-zero\nvalue for the KEY_BLOCK_SIZE table option for the whole\ntable, then the table will implicitly be created with the\nROW_FORMAT table option set to COMPRESSED. However, this\ndoes not happen if you just set the KEY_BLOCK_SIZE index\noption for one or more indexes in the table. The InnoDB\nstorage engine ignores the KEY_BLOCK_SIZE index option.\nHowever, the SHOW CREATE TABLE statement may still report it\nfor the index.\n \nFor information about the KEY_BLOCK_SIZE index option, see\nthe KEY_BLOCK_SIZE table option below.\n \nIndex Types\n \nEach storage engine supports some or all index types. See\nStorage Engine Index Types for details on permitted index\ntypes for each storage engine.\n \nDifferent index types are optimized for different kind of\noperations:\nBTREE is the default type, a','','https://mariadb.com/kb/en/library/create-table/'); -update help_topic set description = CONCAT(description, 'nd normally is the best choice.\nIt is supported by all storage engines. It can be used to\ncompare a column\'s value with a value using the =, >, >=,\n0) ,b int check (b> 0), constraint abc check (a>b));\n \nIf you use the second format and you don\'t give a name to\nthe constraint, then the constraint will get a auto\ngenerated name. This is done so that you can later delete\nthe constraint with ALTER TABLE DROP constraint_name.\n \nOne can disable all constraint expression checks by setting\nthe variable check_constraint_checks to OFF. This is useful\nfor example when loading a table that violates some\nconstraints that you want to later find and fix in SQL.\n \nSee CONSTRAINT for more information.\n \nTable Options\n \nFor each individual table you create (or alter), you can set\nsome table options. The general syntax for setting options\nis:\n \n = , [ = ...]\n \nThe equal sign is optional.\n \nSome options are supported by the server and can be used for\nall tables, no matter what storage engine they use; other\noptions can be specified for all storage engines, but have a\nmeaning only for some engines. Also, engines can extend\nCREATE TABLE with new options.\n \nIf the IGNORE_BAD_TABLE_OPTIONS SQL_MODE is enabled, wrong\ntable options generate a warning; otherwise, they generate\nan error.\n \ntable_option: \n [STORAGE] ENGINE [=] engine_name\n | AUTO_INCREMENT [=] value\n | AVG_ROW_LENGTH [=] value\n | [DEFAULT] CHARACTER SET [=] charset_name\n | CHECKSUM [=] {0 | 1}\n | [DEFAULT] COLLATE [=] collation_name\n | COMMENT [=] \'string\'\n | CONNECTION [=] \'connect_string\'\n | DATA DIRECTORY [=] \'absolute path to directory\'\n | DELAY_KEY_WRITE [=] {0 | 1}\n | ENCRYPTED [=] {YES | NO}\n | ENCRYPTION_KEY_ID [=] value\n | IETF_QUOTES [=] {YES | NO}\n | INDEX DIRECTORY [=] \'absolute path to directory\'\n | INSERT_METHOD [=] { NO | FIRST | LAST }\n | KEY_BLOCK_SIZE [=] value\n | MAX_ROWS [=] value\n | MIN_ROWS [=] value\n | PACK_KEYS [=] {0 | 1 | DEFAULT}\n | PAGE_CHECKSUM [=] {0 | 1}\n | PAGE_COMPRESSED [=] {0 | 1}\n | PAGE_COMPRESSION_LEVEL [=] {0 .. 9}\n | PASSWORD [=] \'string\'\n | ROW_FORMAT [=]\n{DEFAULT|DYNAMIC|FIXED|COMPRESSED|REDUNDANT|COMPACT|PAGE}\n | SEQUENCE [=] {0|1}\n | STATS_AUTO_RECALC [=] {DEFAULT|0|1}\n | STATS_PERSISTENT [=] {DEFAULT|0|1}\n | STATS_SAMPLE_PAGES [=] {DEFAULT|value}\n | TABLESPACE tablespace_name\n | TRANSACTIONAL [=] {0 | 1}\n | UNION [=] (tbl_name[,tbl_name]...)\n | WITH SYSTEM VERSIONING\n \n[STORAGE] ENGINE\n \n[STORAGE] ENGINE specifies a storage engine for the table.\nIf this option is not used, the default storage engine is\nused instead. That is, the storage_engine session option\nvalue if it is set, or the value specified for the\n--default-storage-engine mysqld startup options, or InnoDB.\nIf the specified storage engine is not installed and active,\nthe default value will be used, unless the\nNO_ENGINE_SUBSTITUTION SQL MODE is set (default since\nMariaDB 10.0). This is only true for CREATE TABLE, not for\nALTER TABLE. For a list of storage engines that are present\nin your server, issue a SHOW ENGINES.\n \nAUTO_INCREMENT\n \nAUTO_INCREMENT specifies the initial value for the\nAUTO_INCREMENT primary key. This works for MyISAM, Aria,\nInnoDB/XtraDB, MEMORY, and ARCHIVE tables. You can change\nthis option with ALTER TABLE, but in that case the new value\nmust be higher than the highest value which is present in\nthe AUTO_INCREMENT column. If the storage engine does not\nsupport this option, you can insert (and then delete) a row\nhaving the wanted value - 1 in the AUTO_INCREMENT column.\n \nAVG_ROW_LENGTH\n \nAVG_ROW_LENGTH is the average rows size. It only applies to\ntables using MyISAM and Aria storage engines that have the\nROW_FORMAT table option set to FIXED format.\n \nMyISAM uses MAX_ROWS and AVG_ROW_LENGTH to decide the\nmaximum size of a table (default: 256TB, or the maximum file\nsize allowed by the system).\n \n[DEFAULT] CHARACTER SET/CHARSET\n \n[DEFAULT] CHARACTER SET (or [DEFAULT] CHARSET) is used to\nset a default character set for the table. This is the\ncharacter set used for all columns where an explicit\ncharacter set is not specified. If this option is omitted or\nDEFAULT is specified, database\'s default character set will\nbe used. See Setting Character Sets and Collations for\ndetails on setting the character sets.\n \nCHECKSUM/TABLE_CHECKSUM\n \nCHECKSUM (or TABLE_CHECKSUM) can be set to 1 to maintain a\nlive checksum for all table\'s rows. This makes write\noperations slower, but CHECKSUM TABLE will be very fast.\nThis option is only supported for MyISAM and Aria tables.\n \n[DEFAULT] COLLATE\n \n[DEFAULT] COLLATE is used to set a default collation for the\ntable. This is the collation used for all columns where an\nexplicit character set is not specified. If this option is\nomitted or DEFAULT is specified, database\'s default option\nwill be used. See Setting Character Sets and Collations for\ndetails on setting the collations\n \nCOMMENT\n \nCOMMENT is a comment for the table. Maximum length is 2048\ncharacters (before mariaDB 5.5 it was 60 characters). Also\nused to define table parameters when creating a Spider\ntable.\n \nCONNECTION\n \nCONNECTION is used to specify a server name or a connection\nstring for a Spider, CONNECT, Federated or FederatedX table.\n \nDATA DIRECTORY/INDEX DIRECTORY\n \nDATA DIRECTORY and INDEX DIRECTORY were only supported for\nMyISAM and Aria, before MariaDB 5.5. Since 5.5, DATA\nDIRECTORY has also been supported by InnoDB if the\ninnodb_file_per_table server system variable is enabled, but\nonly in CREATE TABLE, not in ALTER TABLE. So, carefully\nchoose a path for InnoDB tables at creation time, because it\ncannot be changed without dropping and re-creating the\ntable. These options specify the paths for data files and\nindex files, respectively. If these options are omitted, the\ndatabase\'s directory will be used to store data files and\nindex files. Note that these table options do not work for\npartitioned tables (use the partition options instead), or\nif the server has been invoked with the\n--skip-symbolic-links startup option. To avoid the\noverwriting of old files with the same name that could be\npresent in the directories, you can use the\n--keep_files_on_create option (an error will be issued if\nfiles already exist). These options are ignored if the\nNO_DIR_IN_CREATE SQL_MODE is enabled (useful for replication\nslaves). Also note that symbolic links cannot be used for\nInnoDB tables.\n \nDATA DIRECTORY works by creating symlinks from where the\ntable would normally have been (inside the datadir) to where\nthe option specifies. For security reasons, to avoid\nbypassing the privilege system, the server does not permit\nsymlinks inside the datadir. Therefore, DATA DIRECTORY\ncannot be used to specify a location inside the datadir. An\nattempt to do so will result in an error 1210 (HY000)\nIncorrect arguments to DATA DIRECTORY.\n \nDELAY_KEY_WRITE\n \nDELAY_KEY_WRITE is supported by MyISAM and Aria, and can be\nset to 1 to speed up write operations. In that case, when\ndata are modified, the indexes are not updated until the\ntable is closed. Writing the changes to the index file\naltogether can be much faster. However, note that this\noption is applied only if the delay_key_write server\nvariable is set to \'ON\'. If it is \'OFF\' the delayed\nindex writes are always disabled, and if it is \'ALL\' the\ndelayed index writes are always used, disregarding the value\nof DELAY_KEY_WRITE.\n \nENCRYPTED\n \nThe ENCRYPTED table option was added in MariaDB 10.1.4\n \nThe ENCRYPTED table option can be used to manually set the\nencryption status of an InnoDB table. See InnoDB / XtraDB\nEncryption for more information.\n \nAria does not currently support the ENCRYPTED table option.\nSee MDEV-18049 about that.\n \nSee Data-at-Rest Encryption for more information.\n \nENCRYPTION_KEY_ID\n \nThe ENCRYPTION_KEY_ID table option was added in MariaDB\n10.1.4\n \nThe ENCRYPTION_KEY_ID table option can be used to manually\nset the encryption key of an InnoDB table. See InnoDB /\nXtraDB Encryption for more information.\n \nAria does not currently support the ENCRYPTION_KEY_ID table\noption. See MDEV-18049 about that.\n \nSee Data-at-Rest Encryption for more information.\n \nIETF_QUOTES\n \nThe IETF_QUOTES option was added in MariaDB 10.1.8\n \nFor the CSV storage engine, the IETF_QUOTES option, when set\nto YES, enables IETF-compatible parsing of embedded quote\nand comma characters. Enabling this option for a table\nimproves compatibility with other tools that use CSV, but is\nnot compatible with MySQL CSV tables, or MariaDB CSV tables\ncreated without this option. Disabled by default.\n \nINSERT_METHOD\n \nINSERT_METHOD is only used with MERGE tables. This option\ndetermines in which underlying table the new rows should be\ninserted. If you set it to \'NO\' (which is the default) no\nnew rows can be added to the table (but you will still be\nable to perform INSERTs directly against the underlying\ntables). FIRST means that the rows are inserted into the\nfirst table, and LAST means that thet are inserted into the\nlast table.\n \nKEY_BLOCK_SIZE\n \nKEY_BLOCK_SIZE is used to determine the size of key blocks,\nin bytes or kilobytes. However, this value is just a hint,\nand the storage engine could modify or ignore it. If\nKEY_BLOCK_SIZE is set to 0, the storage engine\'s default\nvalue will be used.\n \nWith the InnoDB storage engine, if you specify a non-zero\nvalue for the KEY_BLOCK_SIZE table option for the whole\ntable, then the table will implicitly be created with the\nROW_FORMAT table option set to COMPRESSED.\n \nMIN_ROWS/MAX_ROWS\n \nMIN_ROWS and MAX_ROWS let the storage engine know how many\nrows you are planning to store as a minimum and as a\nmaximum. These values will not be used as real limits, but\nthey help the storage engine to optimize the table. MIN_ROWS\nis only used by MEMORY storage engine to decide the minimum\nmemory that is always allocated. MAX_ROWS is used to decide\nthe minimum size for indexes.\n \nPACK_KEYS\n \nPACK_KEYS can be used to determine whether the indexes will\nbe compressed. Set it to 1 to compress all keys. With a\nvalue of 0, compression will not be used. With the DEFAULT\nvalue, only long strings will be compressed. Uncompressed\nkeys are faster.\n \nPAGE_CHECKSUM\n \nPAGE_CHECKSUM is only applicable to Aria tables, and\ndetermines whether indexes and data should use page\nchecksums for extra safety. \n \nPAGE_COMPRESSED\n \nPAGE_COMPRESSED is used to enable InnoDB page compression\nfor InnoDB tables.\n \nPAGE_COMPRESSION_LEVEL\n \nPAGE_COMPRESSION_LEVEL is used to set the compression level\nfor InnoDB page compression for InnoDB tables. The table\nmust also have the PAGE_COMPRESSED table option set to 1.\n \nValid values for PAGE_COMPRESSION_LEVEL are 1 (the best\nspeed) through 9 (the best compression), .\n \nPASSWORD\n \nPASSWORD is unused.\n \nRAID_TYPE\n \nRAID_TYPE is an obsolete option, as the raid support has\nbeen disabled since MySQL 5.0.\n \nROW_FORMAT\n \nThe ROW_FORMAT table option specifies the row format for the\ndata file. Possible values are engine-dependent.\n \nSupported MyISAM Row Formats\n \nFor MyISAM, the supported row formats are: \nFIXED\nDYNAMIC\nCOMPRESSED\n \nThe COMPRESSED row format can only be set by the myisampack\ncommand line tool.\n \nSee MyISAM Storage Formats for more information.\n \nSupported Aria Row Formats\n \nFor Aria, the supported row formats are:\nPAGE\nFIXED\nDYNAMIC.\n \nSee Aria Storage Formats for more information.\n \nSupported InnoDB Row Formats\n \nFor InnoDB/XtraDB, the supported row formats are:\nCOMPACT\nREDUNDANT\nCOMPRESSED\nDYNAMIC.\n \nIf the ROW_FORMAT table option is set to FIXED for an InnoDB\ntable, then the server will either return an error or a\nwarning depending on the value of the innodb_strict_mode\nsystem variable. If the innodb_strict_mode system variable\nis set to OFF, then a warning is issued, and MariaDB will\ncreate the table using the default row format for the\nspecific MariaDB server version. If the innodb_strict_mode\nsystem variable is set to ON, then an error will be raised.\n \nSee XtraDB/InnoDB Storage Formats for more information.\n \nOther Storage Engines and ROW_FORMAT\n \nOther storage engines do not support the ROW_FORMAT table\noption.\n \nSEQUENCE\n \nIf the table is a sequence, then it will have the SEQUENCE\nset to 1.\n \nSTATS_AUTO_RECALC\n \nSTATS_AUTO_RECALC is available only in MariaDB 10.0+. It\nindicates whether to automatically recalculate persistent\nstatistics (see STATS_PERSISTENT, below) for an InnoDB\ntable.\nIf set to 1, statistics will be recalculated when more than\n10% of the data has changed. When set to 0, stats will be\nrecalculated only when an ANALYZE TABLE is run. If set to\nDEFAULT, or left out, the value set by the\ninnodb_stats_auto_recalc system variable applies. See InnoDB\nPersistent Statistics.\n \nSTATS_PERSISTENT\n \nSTATS_PERSISTENT is available only in MariaDB 10.0+. It\nindicates whether the InnoDB statistics created by ANALYZE\nTABLE will remain on disk or not. It can be set to 1 (on\ndisk), 0 (not on disk, the pre-MariaDB 10 behavior), or\nDEFAULT (the same as leaving out the option), in which case\nthe value set by the innodb_stats_persistent system variable\nwill apply. Persistent statistics stored on disk allow the\nstatistics to survive server restarts, and provide better\nquery plan stability. See InnoDB Persistent Statistics.\n \nSTATS_SAMPLE_PAGES\n \nSTATS_SAMPLE_PAGES is available only in MariaDB 10.0+. It\nindicates how many pages are used to sample index\nstatistics. If 0 or DEFAULT, the default value, the\ninnodb_stats_sample_pages value is used. See InnoDB\nPersistent Statistics.\n \nTRANSACTIONAL\n \nTRANSACTIONAL is only applicable for Aria tables. In future\nAria tables created with this option will be fully\ntransactional, but currently this provides a form of crash\nprotection. See Aria Storage Engine for more details.\n \nUNION\n \nUNION must be specified when you create a MERGE table. This\noption contains a comma-separated list of MyISAM tables\nwhich are accessed by the new table. The list is enclosed\nbetween parenthesis. Example: UNION = (t1,t2)\n \nWITH SYSTEM VERSIONING\n \nWITH SYSTEM VERSIONING is used for creating System-versioned\ntables.\n \nPartitions\n \npartition_options:\n PARTITION BY\n { [LINEAR] HASH(expr)\n | [LINEAR] KEY(column_list)\n | RANGE(expr)\n | LIST(expr)\n | SYSTEM_TIME [INTERVAL time_quantity time_unit] [LIMIT\nnum] }\n [PARTITIONS num]\n [SUBPARTITION BY\n { [LINEAR] HASH(expr)\n | [LINEAR] KEY(column_list) }\n [SUBPARTITIONS num]\n ]\n [(partition_definition [, partition_definition] ...)]\n \npartition_definition:\n PARTITION partition_name\n [VALUES {LESS THAN {(expr) | MAXVALUE} | IN (value_list)}]\n [[STORAGE] ENGINE [=] engine_name]\n [COMMENT [=] \'comment_text\' ]\n [DATA DIRECTORY [=] \'data_dir\']\n [INDEX DIRECTORY [=] \'index_dir\']\n [MAX_ROWS [=] max_number_of_rows]\n [MIN_ROWS [=] min_number_of_rows]\n [TABLESPACE [=] tablespace_name]\n [NODEGROUP [=] node_group_id]\n [(subpartition_definition [, subpartition_definition] ...)]\n \nsubpartition_definition:\n SUBPARTITION logical_name\n [[STORAGE] ENGINE [=] engine_name]\n [COMMENT [=] \'comment_text\' ]\n [DATA DIRECTORY [=] \'data_dir\']\n [INDEX DIRECTORY [=] \'index_dir\']\n [MAX_ROWS [=] max_number_of_rows]\n [MIN_ROWS [=] min_number_of_rows]\n [TABLESPACE [=] tablespace_name]\n [NODEGROUP [=] node_group_id]\nIf the PARTITION BY clause is used, the table will be\npartitioned. A partition method must be explicitly indicated\nfor partitions and subpartitions. Partition methods are:\n[LINEAR] HASH creates a hash key which will be used to read\nand write rows. The partition function can be any valid SQL\nexpression which returns an INTEGER number. Thus, it is\npossible to use the HASH method on an integer column, or on\nfunctions which accept integer columns as an argument.\nHowever, VALUES LESS THAN and VALUES IN clauses can not be\nused with HASH. An example:\n \nCREATE TABLE t1 (a INT, b CHAR(5), c DATETIME)\n PARTITION BY HASH ( YEAR(c) );\n \n [LINEAR] HASH can be used for subpartitions, too.\n[LINEAR] KEY is similar to HASH, but the index has an even\ndistribution of data. Also, the expression can only be a\ncolumn or a list of columns. VALUES LESS THAN and VALUES IN\nclauses can not be used with KEY.\nRANGE partitions the rows using on a range of values, using\nthe VALUES LESS THAN operator. VALUES IN is not allowed with\nRANGE. The partition function can be any valid SQL\nexpression which returns a single value.\nLIST assignes partitions based on a table\'s column with a\nrestricted set of possible values. It is similar to RANGE,\nbut VALUES IN must be used for at least 1 columns, and\nVALUES LESS THAN is disallowed.\nSYSTEM_TIME partitioning is used for System-versioned tables\nto store historical data separately from current data.\n \nOnly HASH and KEY can be used for subpartitions, and they\ncan be [LINEAR].\n \nIt is possible to define up to 1024 partitions and\nsubpartitions.\n \nThe number of defined partitions can be optionally specified\nas PARTITION count. This can be done to avoid specifying all\npartitions individually. But you can also declare each\nindividual partition and, additionally, specify a PARTITIONS\ncount clause; in the case, the number of PARTITIONs must\nequal count.\n \nAlso see Partitioning Types Overview.\n \nSequences\n \nCREATE TABLE can also be used to create a SEQUENCE. See\nCREATE SEQUENCE and Sequence Overview.\n \nExamples\n-------- \ncreate table if not exists test (\na bigint auto_increment primary key,\nname varchar(128) charset utf8,\nkey name (name(32))\n) engine=InnoDB default charset latin1;\n \nThis example shows a couple of things:\nUsage of IF NOT EXISTS; If the table already existed, it\nwill not be created. There will not be any error for the\nclient, just a warning.\nHow to create a PRIMARY KEY that is automatically generated.\nHow to specify a table-specific character set and another\nfor a column.\nHow to create an index (name) that is only partly indexed\n(to save space).\n \nThe following clauses will work from MariaDB 10.2.1 only.\n \nCREATE TABLE t1(\n a int DEFAULT (1+1),\n b int DEFAULT (a+1),\n expires DATETIME DEFAULT(NOW() + INTERVAL 1 YEAR),\n x BLOB DEFAULT USER()\n);\n \n\n\nURL: https://mariadb.com/kb/en/library/create-table/') WHERE help_topic_id = 660; +update help_topic set description = CONCAT(description, 'nd normally is the best choice.\nIt is supported by all storage engines. It can be used to\ncompare a column\'s value with a value using the =, >, >=,\n0) ,b int check (b> 0), constraint abc check (a>b));\n \nIf you use the second format and you don\'t give a name to\nthe constraint, then the constraint will get a auto\ngenerated name. This is done so that you can later delete\nthe constraint with ALTER TABLE DROP constraint_name.\n \nOne can disable all constraint expression checks by setting\nthe variable check_constraint_checks to OFF. This is useful\nfor example when loading a table that violates some\nconstraints that you want to later find and fix in SQL.\n \nSee CONSTRAINT for more information.\n \nTable Options\n \nFor each individual table you create (or alter), you can set\nsome table options. The general syntax for setting options\nis:\n \n = , [ = ...]\n \nThe equal sign is optional.\n \nSome options are supported by the server and can be used for\nall tables, no matter what storage engine they use; other\noptions can be specified for all storage engines, but have a\nmeaning only for some engines. Also, engines can extend\nCREATE TABLE with new options.\n \nIf the IGNORE_BAD_TABLE_OPTIONS SQL_MODE is enabled, wrong\ntable options generate a warning; otherwise, they generate\nan error.\n \ntable_option: \n [STORAGE] ENGINE [=] engine_name\n | AUTO_INCREMENT [=] value\n | AVG_ROW_LENGTH [=] value\n | [DEFAULT] CHARACTER SET [=] charset_name\n | CHECKSUM [=] {0 | 1}\n | [DEFAULT] COLLATE [=] collation_name\n | COMMENT [=] \'string\'\n | CONNECTION [=] \'connect_string\'\n | DATA DIRECTORY [=] \'absolute path to directory\'\n | DELAY_KEY_WRITE [=] {0 | 1}\n | ENCRYPTED [=] {YES | NO}\n | ENCRYPTION_KEY_ID [=] value\n | IETF_QUOTES [=] {YES | NO}\n | INDEX DIRECTORY [=] \'absolute path to directory\'\n | INSERT_METHOD [=] { NO | FIRST | LAST }\n | KEY_BLOCK_SIZE [=] value\n | MAX_ROWS [=] value\n | MIN_ROWS [=] value\n | PACK_KEYS [=] {0 | 1 | DEFAULT}\n | PAGE_CHECKSUM [=] {0 | 1}\n | PAGE_COMPRESSED [=] {0 | 1}\n | PAGE_COMPRESSION_LEVEL [=] {0 .. 9}\n | PASSWORD [=] \'string\'\n | ROW_FORMAT [=]\n{DEFAULT|DYNAMIC|FIXED|COMPRESSED|REDUNDANT|COMPACT|PAGE}\n | SEQUENCE [=] {0|1}\n | STATS_AUTO_RECALC [=] {DEFAULT|0|1}\n | STATS_PERSISTENT [=] {DEFAULT|0|1}\n | STATS_SAMPLE_PAGES [=] {DEFAULT|value}\n | TABLESPACE tablespace_name\n | TRANSACTIONAL [=] {0 | 1}\n | UNION [=] (tbl_name[,tbl_name]...)\n | WITH SYSTEM VERSIONING\n \n[STORAGE] ENGINE\n \n[STORAGE] ENGINE specifies a storage engine for the table.\nIf this option is not used, the default storage engine is\nused instead. That is, the default_storage_engine session option\nvalue if it is set, or the value specified for the\n--default-storage-engine mysqld startup options, or InnoDB.\nIf the specified storage engine is not installed and active,\nthe default value will be used, unless the\nNO_ENGINE_SUBSTITUTION SQL MODE is set (default since\nMariaDB 10.0). This is only true for CREATE TABLE, not for\nALTER TABLE. For a list of storage engines that are present\nin your server, issue a SHOW ENGINES.\n \nAUTO_INCREMENT\n \nAUTO_INCREMENT specifies the initial value for the\nAUTO_INCREMENT primary key. This works for MyISAM, Aria,\nInnoDB/XtraDB, MEMORY, and ARCHIVE tables. You can change\nthis option with ALTER TABLE, but in that case the new value\nmust be higher than the highest value which is present in\nthe AUTO_INCREMENT column. If the storage engine does not\nsupport this option, you can insert (and then delete) a row\nhaving the wanted value - 1 in the AUTO_INCREMENT column.\n \nAVG_ROW_LENGTH\n \nAVG_ROW_LENGTH is the average rows size. It only applies to\ntables using MyISAM and Aria storage engines that have the\nROW_FORMAT table option set to FIXED format.\n \nMyISAM uses MAX_ROWS and AVG_ROW_LENGTH to decide the\nmaximum size of a table (default: 256TB, or the maximum file\nsize allowed by the system).\n \n[DEFAULT] CHARACTER SET/CHARSET\n \n[DEFAULT] CHARACTER SET (or [DEFAULT] CHARSET) is used to\nset a default character set for the table. This is the\ncharacter set used for all columns where an explicit\ncharacter set is not specified. If this option is omitted or\nDEFAULT is specified, database\'s default character set will\nbe used. See Setting Character Sets and Collations for\ndetails on setting the character sets.\n \nCHECKSUM/TABLE_CHECKSUM\n \nCHECKSUM (or TABLE_CHECKSUM) can be set to 1 to maintain a\nlive checksum for all table\'s rows. This makes write\noperations slower, but CHECKSUM TABLE will be very fast.\nThis option is only supported for MyISAM and Aria tables.\n \n[DEFAULT] COLLATE\n \n[DEFAULT] COLLATE is used to set a default collation for the\ntable. This is the collation used for all columns where an\nexplicit character set is not specified. If this option is\nomitted or DEFAULT is specified, database\'s default option\nwill be used. See Setting Character Sets and Collations for\ndetails on setting the collations\n \nCOMMENT\n \nCOMMENT is a comment for the table. Maximum length is 2048\ncharacters (before mariaDB 5.5 it was 60 characters). Also\nused to define table parameters when creating a Spider\ntable.\n \nCONNECTION\n \nCONNECTION is used to specify a server name or a connection\nstring for a Spider, CONNECT, Federated or FederatedX table.\n \nDATA DIRECTORY/INDEX DIRECTORY\n \nDATA DIRECTORY and INDEX DIRECTORY were only supported for\nMyISAM and Aria, before MariaDB 5.5. Since 5.5, DATA\nDIRECTORY has also been supported by InnoDB if the\ninnodb_file_per_table server system variable is enabled, but\nonly in CREATE TABLE, not in ALTER TABLE. So, carefully\nchoose a path for InnoDB tables at creation time, because it\ncannot be changed without dropping and re-creating the\ntable. These options specify the paths for data files and\nindex files, respectively. If these options are omitted, the\ndatabase\'s directory will be used to store data files and\nindex files. Note that these table options do not work for\npartitioned tables (use the partition options instead), or\nif the server has been invoked with the\n--skip-symbolic-links startup option. To avoid the\noverwriting of old files with the same name that could be\npresent in the directories, you can use the\n--keep_files_on_create option (an error will be issued if\nfiles already exist). These options are ignored if the\nNO_DIR_IN_CREATE SQL_MODE is enabled (useful for replication\nslaves). Also note that symbolic links cannot be used for\nInnoDB tables.\n \nDATA DIRECTORY works by creating symlinks from where the\ntable would normally have been (inside the datadir) to where\nthe option specifies. For security reasons, to avoid\nbypassing the privilege system, the server does not permit\nsymlinks inside the datadir. Therefore, DATA DIRECTORY\ncannot be used to specify a location inside the datadir. An\nattempt to do so will result in an error 1210 (HY000)\nIncorrect arguments to DATA DIRECTORY.\n \nDELAY_KEY_WRITE\n \nDELAY_KEY_WRITE is supported by MyISAM and Aria, and can be\nset to 1 to speed up write operations. In that case, when\ndata are modified, the indexes are not updated until the\ntable is closed. Writing the changes to the index file\naltogether can be much faster. However, note that this\noption is applied only if the delay_key_write server\nvariable is set to \'ON\'. If it is \'OFF\' the delayed\nindex writes are always disabled, and if it is \'ALL\' the\ndelayed index writes are always used, disregarding the value\nof DELAY_KEY_WRITE.\n \nENCRYPTED\n \nThe ENCRYPTED table option was added in MariaDB 10.1.4\n \nThe ENCRYPTED table option can be used to manually set the\nencryption status of an InnoDB table. See InnoDB / XtraDB\nEncryption for more information.\n \nAria does not currently support the ENCRYPTED table option.\nSee MDEV-18049 about that.\n \nSee Data-at-Rest Encryption for more information.\n \nENCRYPTION_KEY_ID\n \nThe ENCRYPTION_KEY_ID table option was added in MariaDB\n10.1.4\n \nThe ENCRYPTION_KEY_ID table option can be used to manually\nset the encryption key of an InnoDB table. See InnoDB /\nXtraDB Encryption for more information.\n \nAria does not currently support the ENCRYPTION_KEY_ID table\noption. See MDEV-18049 about that.\n \nSee Data-at-Rest Encryption for more information.\n \nIETF_QUOTES\n \nThe IETF_QUOTES option was added in MariaDB 10.1.8\n \nFor the CSV storage engine, the IETF_QUOTES option, when set\nto YES, enables IETF-compatible parsing of embedded quote\nand comma characters. Enabling this option for a table\nimproves compatibility with other tools that use CSV, but is\nnot compatible with MySQL CSV tables, or MariaDB CSV tables\ncreated without this option. Disabled by default.\n \nINSERT_METHOD\n \nINSERT_METHOD is only used with MERGE tables. This option\ndetermines in which underlying table the new rows should be\ninserted. If you set it to \'NO\' (which is the default) no\nnew rows can be added to the table (but you will still be\nable to perform INSERTs directly against the underlying\ntables). FIRST means that the rows are inserted into the\nfirst table, and LAST means that thet are inserted into the\nlast table.\n \nKEY_BLOCK_SIZE\n \nKEY_BLOCK_SIZE is used to determine the size of key blocks,\nin bytes or kilobytes. However, this value is just a hint,\nand the storage engine could modify or ignore it. If\nKEY_BLOCK_SIZE is set to 0, the storage engine\'s default\nvalue will be used.\n \nWith the InnoDB storage engine, if you specify a non-zero\nvalue for the KEY_BLOCK_SIZE table option for the whole\ntable, then the table will implicitly be created with the\nROW_FORMAT table option set to COMPRESSED.\n \nMIN_ROWS/MAX_ROWS\n \nMIN_ROWS and MAX_ROWS let the storage engine know how many\nrows you are planning to store as a minimum and as a\nmaximum. These values will not be used as real limits, but\nthey help the storage engine to optimize the table. MIN_ROWS\nis only used by MEMORY storage engine to decide the minimum\nmemory that is always allocated. MAX_ROWS is used to decide\nthe minimum size for indexes.\n \nPACK_KEYS\n \nPACK_KEYS can be used to determine whether the indexes will\nbe compressed. Set it to 1 to compress all keys. With a\nvalue of 0, compression will not be used. With the DEFAULT\nvalue, only long strings will be compressed. Uncompressed\nkeys are faster.\n \nPAGE_CHECKSUM\n \nPAGE_CHECKSUM is only applicable to Aria tables, and\ndetermines whether indexes and data should use page\nchecksums for extra safety. \n \nPAGE_COMPRESSED\n \nPAGE_COMPRESSED is used to enable InnoDB page compression\nfor InnoDB tables.\n \nPAGE_COMPRESSION_LEVEL\n \nPAGE_COMPRESSION_LEVEL is used to set the compression level\nfor InnoDB page compression for InnoDB tables. The table\nmust also have the PAGE_COMPRESSED table option set to 1.\n \nValid values for PAGE_COMPRESSION_LEVEL are 1 (the best\nspeed) through 9 (the best compression), .\n \nPASSWORD\n \nPASSWORD is unused.\n \nRAID_TYPE\n \nRAID_TYPE is an obsolete option, as the raid support has\nbeen disabled since MySQL 5.0.\n \nROW_FORMAT\n \nThe ROW_FORMAT table option specifies the row format for the\ndata file. Possible values are engine-dependent.\n \nSupported MyISAM Row Formats\n \nFor MyISAM, the supported row formats are: \nFIXED\nDYNAMIC\nCOMPRESSED\n \nThe COMPRESSED row format can only be set by the myisampack\ncommand line tool.\n \nSee MyISAM Storage Formats for more information.\n \nSupported Aria Row Formats\n \nFor Aria, the supported row formats are:\nPAGE\nFIXED\nDYNAMIC.\n \nSee Aria Storage Formats for more information.\n \nSupported InnoDB Row Formats\n \nFor InnoDB/XtraDB, the supported row formats are:\nCOMPACT\nREDUNDANT\nCOMPRESSED\nDYNAMIC.\n \nIf the ROW_FORMAT table option is set to FIXED for an InnoDB\ntable, then the server will either return an error or a\nwarning depending on the value of the innodb_strict_mode\nsystem variable. If the innodb_strict_mode system variable\nis set to OFF, then a warning is issued, and MariaDB will\ncreate the table using the default row format for the\nspecific MariaDB server version. If the innodb_strict_mode\nsystem variable is set to ON, then an error will be raised.\n \nSee XtraDB/InnoDB Storage Formats for more information.\n \nOther Storage Engines and ROW_FORMAT\n \nOther storage engines do not support the ROW_FORMAT table\noption.\n \nSEQUENCE\n \nIf the table is a sequence, then it will have the SEQUENCE\nset to 1.\n \nSTATS_AUTO_RECALC\n \nSTATS_AUTO_RECALC is available only in MariaDB 10.0+. It\nindicates whether to automatically recalculate persistent\nstatistics (see STATS_PERSISTENT, below) for an InnoDB\ntable.\nIf set to 1, statistics will be recalculated when more than\n10% of the data has changed. When set to 0, stats will be\nrecalculated only when an ANALYZE TABLE is run. If set to\nDEFAULT, or left out, the value set by the\ninnodb_stats_auto_recalc system variable applies. See InnoDB\nPersistent Statistics.\n \nSTATS_PERSISTENT\n \nSTATS_PERSISTENT is available only in MariaDB 10.0+. It\nindicates whether the InnoDB statistics created by ANALYZE\nTABLE will remain on disk or not. It can be set to 1 (on\ndisk), 0 (not on disk, the pre-MariaDB 10 behavior), or\nDEFAULT (the same as leaving out the option), in which case\nthe value set by the innodb_stats_persistent system variable\nwill apply. Persistent statistics stored on disk allow the\nstatistics to survive server restarts, and provide better\nquery plan stability. See InnoDB Persistent Statistics.\n \nSTATS_SAMPLE_PAGES\n \nSTATS_SAMPLE_PAGES is available only in MariaDB 10.0+. It\nindicates how many pages are used to sample index\nstatistics. If 0 or DEFAULT, the default value, the\ninnodb_stats_sample_pages value is used. See InnoDB\nPersistent Statistics.\n \nTRANSACTIONAL\n \nTRANSACTIONAL is only applicable for Aria tables. In future\nAria tables created with this option will be fully\ntransactional, but currently this provides a form of crash\nprotection. See Aria Storage Engine for more details.\n \nUNION\n \nUNION must be specified when you create a MERGE table. This\noption contains a comma-separated list of MyISAM tables\nwhich are accessed by the new table. The list is enclosed\nbetween parenthesis. Example: UNION = (t1,t2)\n \nWITH SYSTEM VERSIONING\n \nWITH SYSTEM VERSIONING is used for creating System-versioned\ntables.\n \nPartitions\n \npartition_options:\n PARTITION BY\n { [LINEAR] HASH(expr)\n | [LINEAR] KEY(column_list)\n | RANGE(expr)\n | LIST(expr)\n | SYSTEM_TIME [INTERVAL time_quantity time_unit] [LIMIT\nnum] }\n [PARTITIONS num]\n [SUBPARTITION BY\n { [LINEAR] HASH(expr)\n | [LINEAR] KEY(column_list) }\n [SUBPARTITIONS num]\n ]\n [(partition_definition [, partition_definition] ...)]\n \npartition_definition:\n PARTITION partition_name\n [VALUES {LESS THAN {(expr) | MAXVALUE} | IN (value_list)}]\n [[STORAGE] ENGINE [=] engine_name]\n [COMMENT [=] \'comment_text\' ]\n [DATA DIRECTORY [=] \'data_dir\']\n [INDEX DIRECTORY [=] \'index_dir\']\n [MAX_ROWS [=] max_number_of_rows]\n [MIN_ROWS [=] min_number_of_rows]\n [TABLESPACE [=] tablespace_name]\n [NODEGROUP [=] node_group_id]\n [(subpartition_definition [, subpartition_definition] ...)]\n \nsubpartition_definition:\n SUBPARTITION logical_name\n [[STORAGE] ENGINE [=] engine_name]\n [COMMENT [=] \'comment_text\' ]\n [DATA DIRECTORY [=] \'data_dir\']\n [INDEX DIRECTORY [=] \'index_dir\']\n [MAX_ROWS [=] max_number_of_rows]\n [MIN_ROWS [=] min_number_of_rows]\n [TABLESPACE [=] tablespace_name]\n [NODEGROUP [=] node_group_id]\nIf the PARTITION BY clause is used, the table will be\npartitioned. A partition method must be explicitly indicated\nfor partitions and subpartitions. Partition methods are:\n[LINEAR] HASH creates a hash key which will be used to read\nand write rows. The partition function can be any valid SQL\nexpression which returns an INTEGER number. Thus, it is\npossible to use the HASH method on an integer column, or on\nfunctions which accept integer columns as an argument.\nHowever, VALUES LESS THAN and VALUES IN clauses can not be\nused with HASH. An example:\n \nCREATE TABLE t1 (a INT, b CHAR(5), c DATETIME)\n PARTITION BY HASH ( YEAR(c) );\n \n [LINEAR] HASH can be used for subpartitions, too.\n[LINEAR] KEY is similar to HASH, but the index has an even\ndistribution of data. Also, the expression can only be a\ncolumn or a list of columns. VALUES LESS THAN and VALUES IN\nclauses can not be used with KEY.\nRANGE partitions the rows using on a range of values, using\nthe VALUES LESS THAN operator. VALUES IN is not allowed with\nRANGE. The partition function can be any valid SQL\nexpression which returns a single value.\nLIST assignes partitions based on a table\'s column with a\nrestricted set of possible values. It is similar to RANGE,\nbut VALUES IN must be used for at least 1 columns, and\nVALUES LESS THAN is disallowed.\nSYSTEM_TIME partitioning is used for System-versioned tables\nto store historical data separately from current data.\n \nOnly HASH and KEY can be used for subpartitions, and they\ncan be [LINEAR].\n \nIt is possible to define up to 1024 partitions and\nsubpartitions.\n \nThe number of defined partitions can be optionally specified\nas PARTITION count. This can be done to avoid specifying all\npartitions individually. But you can also declare each\nindividual partition and, additionally, specify a PARTITIONS\ncount clause; in the case, the number of PARTITIONs must\nequal count.\n \nAlso see Partitioning Types Overview.\n \nSequences\n \nCREATE TABLE can also be used to create a SEQUENCE. See\nCREATE SEQUENCE and Sequence Overview.\n \nExamples\n-------- \ncreate table if not exists test (\na bigint auto_increment primary key,\nname varchar(128) charset utf8,\nkey name (name(32))\n) engine=InnoDB default charset latin1;\n \nThis example shows a couple of things:\nUsage of IF NOT EXISTS; If the table already existed, it\nwill not be created. There will not be any error for the\nclient, just a warning.\nHow to create a PRIMARY KEY that is automatically generated.\nHow to specify a table-specific character set and another\nfor a column.\nHow to create an index (name) that is only partly indexed\n(to save space).\n \nThe following clauses will work from MariaDB 10.2.1 only.\n \nCREATE TABLE t1(\n a int DEFAULT (1+1),\n b int DEFAULT (a+1),\n expires DATETIME DEFAULT(NOW() + INTERVAL 1 YEAR),\n x BLOB DEFAULT USER()\n);\n \n\n\nURL: https://mariadb.com/kb/en/library/create-table/') WHERE help_topic_id = 660; insert into help_topic (help_topic_id,help_category_id,name,description,example,url) values (661,39,'CREATE TABLESPACE','The CREATE TABLESPACE statement is not supported by MariaDB.\nIt was originally inherited from MySQL NDB Cluster. In MySQL\n5.7 and later, the statement is also supported for InnoDB.\nHowever, MariaDB has chosen not to include that specific\nfeature. See MDEV-19294 for more information.\n \n\n \n \n \n \n \n \n \n\nURL: https://mariadb.com/kb/en/library/create-tablespace/','','https://mariadb.com/kb/en/library/create-tablespace/'); insert into help_topic (help_topic_id,help_category_id,name,description,example,url) values (662,39,'CREATE TRIGGER','Syntax\n------ \nCREATE [OR REPLACE]\n [DEFINER = { user | CURRENT_USER | role | CURRENT_ROLE }]\n TRIGGER [IF NOT EXISTS] trigger_name trigger_time\ntrigger_event\n ON tbl_name FOR EACH ROW\n [{ FOLLOWS | PRECEDES } other_trigger_name ]\n trigger_stmt\n \nDescription\n----------- \nThis statement creates a new trigger. A trigger is a named\ndatabase\nobject that is associated with a table, and that activates\nwhen a\nparticular event occurs for the table. The trigger becomes\nassociated\nwith the table named tbl_name, which must refer to a\npermanent table.\nYou cannot associate a trigger with a TEMPORARY table or a\nview.\n \nCREATE TRIGGER requires the TRIGGER privilege for the table\nassociated\nwith the trigger. (Before MySQL 5.1.6, this statement\nrequires the\nSUPER privilege.)\n \nYou can have multiple triggers for the same trigger_time and\ntrigger_event.\n \nFor valid identifiers to use as trigger names, see\nIdentifier Names.\n \nOR REPLACE\n \nIf used and the trigger already exists, instead of an error\nbeing returned, the existing trigger will be dropped and\nreplaced by the newly defined trigger.\n \nDEFINER\n \nThe DEFINER clause determines the security context to be\nused when\nchecking access privileges at trigger activation time.\n \nIF NOT EXISTS\n \nIf the IF NOT EXISTS clause is used, the trigger will only\nbe created if a trigger of the same name does not exist. If\nthe trigger already exists, by default a warning will be\nreturned.\n \ntrigger_time\n \ntrigger_time is the trigger action time. It can be BEFORE or\nAFTER to\nindicate that the trigger activates before or after each row\nto be\nmodified.\n \ntrigger_event\n \ntrigger_event indicates the kind of statement that activates\nthe\ntrigger. The trigger_event can be one of the following:\nINSERT: The trigger is activated whenever a new row is\ninserted into the table; for example, through INSERT, LOAD\nDATA, and REPLACE statements.\nUPDATE: The trigger is activated whenever a row is modified;\nfor example, through UPDATE statements.\nDELETE: The trigger is activated whenever a row is deleted\nfrom the table; for example, through DELETE and REPLACE\nstatements. However, DROP TABLE and TRUNCATE statements on\nthe table do not activate this trigger, because they do not\nuse DELETE. Dropping a partition does not activate DELETE\ntriggers, either.\n \nFOLLOWS/PRECEDES other_trigger_name\n \nThe FOLLOWS other_trigger_name and PRECEDES\nother_trigger_name options were added in MariaDB 10.2.3 as\npart of supporting multiple triggers per action time.\nThis is the same syntax used by MySQL 5.7, although MySQL\n5.7 does not have multi-trigger support.\n \nFOLLOWS adds the new trigger after another trigger while\nPRECEDES adds the new trigger before another trigger. If\nneither option is used, the new trigger is added last for\nthe given action and time.\n \nFOLLOWS and PRECEDES are not stored in the trigger\ndefinition. However the trigger order is guaranteed to not\nchange over time. mysqldump and other backup methods will\nnot change trigger order.\nYou can verify the trigger order from the ACTION_ORDER\ncolumn in INFORMATION_SCHEMA.TRIGGERS table.\n \nSELECT trigger_name, action_order FROM\ninformation_schema.triggers \n WHERE event_object_table=\'t1\';\n \nExamples\n-------- \nCREATE DEFINER=`root`@`localhost` TRIGGER increment_animal\n AFTER INSERT ON animals FOR EACH ROW \n UPDATE animal_count SET animal_count.animals =\nanimal_count.animals+1;\n \nOR REPLACE and IF NOT EXISTS\n \nCREATE DEFINER=`root`@`localhost` TRIGGER increment_animal\n AFTER INSERT ON animals FOR EACH ROW\n UPDATE animal_count SET animal_count.animals =\nanimal_count.animals+1;\n \nERROR 1359 (HY000): Trigger already exists\n \nCREATE OR REPLACE DEFINER=`root`@`localhost` TRIGGER\nincrement_animal\n AFTER INSERT ON animals FOR EACH ROW\n UPDATE animal_count SET animal_count.animals =\nanimal_count.animals+1;\n \nQuery OK, 0 rows affected (0.12 sec)\n \nCREATE DEFINER=`root`@`localhost` TRIGGER IF NOT EXISTS\nincrement_animal\n AFTER INSERT ON animals FOR EACH ROW\n UPDATE animal_count SET animal_count.animals =\nanimal_count.animals+1;\n \nQuery OK, 0 rows affected, 1 warning (0.00 sec)\n \nSHOW WARNINGS;\n \n+-------+------+------------------------+\n| Level | Code | Message |\n+-------+------+------------------------+\n| Note | 1359 | Trigger already exists |\n+-------+------+------------------------+\n1 row in set (0.00 sec)\n \n\n\nURL: https://mariadb.com/kb/en/library/create-trigger/','','https://mariadb.com/kb/en/library/create-trigger/'); insert into help_topic (help_topic_id,help_category_id,name,description,example,url) values (663,39,'CREATE VIEW','Syntax\n------ \nCREATE\n [OR REPLACE]\n [ALGORITHM = {UNDEFINED | MERGE | TEMPTABLE}]\n [DEFINER = { user | CURRENT_USER | role | CURRENT_ROLE }]\n [SQL SECURITY { DEFINER | INVOKER }]\n VIEW [IF NOT EXISTS] view_name [(column_list)]\n AS select_statement\n [WITH [CASCADED | LOCAL] CHECK OPTION]\n \nDescription\n----------- \nThe CREATE VIEW statement creates a new view, or replaces an\nexisting\none if the OR REPLACE clause is given. If the view does not\nexist, CREATE OR\nREPLACE VIEW is the same as CREATE VIEW. If the view does\nexist, CREATE OR\nREPLACE VIEW is the same as ALTER VIEW.\n \nThe select_statement is a SELECT statement that provides the\ndefinition of\nthe view. (When you select from the view, you select in\neffect using the SELECT\nstatement.) select_statement can select from base tables or\nother views.\n \nThe view definition is \"frozen\" at creation time, so\nchanges to the underlying\ntables afterwards do not affect the view definition. For\nexample, if a view is\ndefined as SELECT * on a table, new columns added to the\ntable later do not\nbecome part of the view. A SHOW CREATE VIEW shows that\nsuch queries are rewritten and column names are included in\nthe view\ndefinition.\n \nThe view definition must be a query that does not return\nerrors at view\ncreation times. However, the base tables used by the views\nmight be altered\nlater and the query may not be valid anymore. In this case,\nquerying the view\nwill result in an error. CHECK TABLE helps in finding this\nkind\nof problems.\n \nThe ALGORITHM clause affects how MariaDB processes the\nview. The DEFINER and SQL SECURITY clauses specify the\nsecurity context to be\nused when checking access privileges at view invocation\ntime. The WITH CHECK\nOPTION clause can be given to constrain inserts or updates\nto rows in tables\nreferenced by the view. These clauses are described later in\nthis section.\n \nThe CREATE VIEW statement requires the CREATE VIEW privilege\nfor the\nview, and some privilege for each column selected by the\nSELECT\nstatement. For columns used elsewhere in the SELECT\nstatement you must\nhave the SELECT privilege. If the OR REPLACE clause is\npresent, you\nmust also have the DROP privilege for the view.\n \nA view belongs to a database. By default, a new view is\ncreated in the\ndefault database. To create the view explicitly in a given\ndatabase,\nspecify the name as db_name.view_name when you create it.\n \nCREATE VIEW test.v AS SELECT * FROM t;\n \nBase tables and views share the same namespace within a\ndatabase, so a\ndatabase cannot contain a base table and a view that have\nthe same\nname.\n \nViews must have unique column names with no duplicates, just\nlike base\ntables. By default, the names of the columns retrieved by\nthe SELECT\nstatement are used for the view column names. To define\nexplicit names\nfor the view columns, the optional column_list clause can be\ngiven as\na list of comma-separated identifiers. The number of names\nin\ncolumn_list must be the same as the number of columns\nretrieved by the\nSELECT statement.\n \nMySQL until 5.1.28\n \nPrior to MySQL 5.1.29, When you modify an existing view, the\ncurrent view definition is backed up and saved. It is stored\nin that\ntable\'s database directory, in a subdirectory named arc.\nThe backup\nfile for a view v is named v.frm-00001. If you alter the\nview again,\nthe next backup is named v.frm-00002. The three latest view\nbackup\ndefinitions are stored. Backed up view definitions are not\npreserved\nby mysqldump, or any other such programs, but you can retain\nthem\nusing a file copy operation. However, they are not needed\nfor anything\nbut to provide you with a backup of your previous view\ndefinition. It\nis safe to remove these backup definitions, but only while\nmysqld is\nnot running. If you delete the arc subdirectory or its files\nwhile\nmysqld is running, you will receive an error the next time\nyou try to\nalter the view: \n \nMariaDB [test]> ALTER VIEW v AS SELECT * FROM t; \nERROR 6 (HY000): Error on delete of\n\'.\\test\\arc/v.frm-0004\' (Errcode: 2)\n \nColumns retrieved by the SELECT statement can be simple\nreferences to\ntable columns. They can also be expressions that use\nfunctions,\nconstant values, operators, and so forth.\n \nUnqualified table or view names in the SELECT statement are\ninterpreted with respect to the default database. A view can\nrefer to\ntables or views in other databases by qualifying the table\nor view\nname with the proper database name.\n \nA view can be created from many kinds of SELECT statements.\nIt can\nrefer to base tables or other views. It can use joins,\nUNION, and\nsubqueries. The SELECT need not even refer to any tables.\nThe\nfollowing example defines a view that selects two columns\nfrom another\ntable, as well as an expression calculated from those\ncolumns:\n \nCREATE TABLE t (qty INT, price INT);\n \nINSERT INTO t VALUES(3, 50);\n \nCREATE VIEW v AS SELECT qty, price, qty*price AS value FROM\nt;\n \nSELECT * FROM v;\n+------+-------+-------+\n| qty | price | value |\n+------+-------+-------+\n| 3 | 50 | 150 |\n+------+-------+-------+\n \nA view definition is subject to the following restrictions:\nThe SELECT statement cannot contain a subquery in the FROM\nclause.\nThe SELECT statement cannot refer to system or user\nvariables.\nWithin a stored program, the definition cannot refer to\nprogram parameters or local variables.\nThe SELECT statement cannot refer to prepared statement\nparameters.\nAny table or view referred to in the definition must exist.\nHowever, after a view has been created, it is possible to\ndrop a table or view that the definition refers to. In this\ncase, use of the view results in an error. To check a view\ndefinition for problems of this kind, use the CHECK TABLE\nstatement.\nThe definition cannot refer to a TEMPORARY table, and you\ncannot create a TEMPORARY view.\nAny tables named in the view definition must exist at\ndefinition time.\nYou cannot associate a trigger with a view.\nFor valid identifiers to use as view names, see Identifier\nNames.\n \nORDER BY is allowed in a view definition, but it is ignored\nif you\nselect from a view using a statement that has its own ORDER\nBY.\n \nFor other options or clauses in the definition, they are\nadded to the\noptions or clauses of the statement that references the\nview, but the\neffect is undefined. For example, if a view definition\nincludes a\nLIMIT clause, and you select from the view using a statement\nthat has\nits own LIMIT clause, it is undefined which limit applies.\nThis same\nprinciple applies to options such as ALL, DISTINCT, or\nSQL_SMALL_RESULT that follow the SELECT keyword, and to\nclauses such\nas INTO, FOR UPDATE, and LOCK IN SHARE MODE.\n \nThe PROCEDURE clause cannot be used in a view definition,\nand it cannot be used if a view is referenced in the FROM\nclause.\n \nIf you create a view and then change the query processing\nenvironment\nby changing system variables, that may affect the results\nthat you get\nfrom the view:\n \nCREATE VIEW v (mycol) AS SELECT \'abc\';\n \nSET sql_mode = \'\';\n \nSELECT \"mycol\" FROM v;\n+-------+\n| mycol |\n+-------+\n| mycol | \n+-------+\n \nSET sql_mode = \'ANSI_QUOTES\';\n \nSELECT \"mycol\" FROM v;\n+-------+\n| mycol |\n+-------+\n| abc | \n+-------+\n \nThe DEFINER and SQL SECURITY clauses determine which MariaDB\naccount to\nuse when checking access privileges for the view when a\nstatement is\nexecuted that references the view. They were added in MySQL\n5.1.2.\nThe legal SQL SECURITY characteristic values are DEFINER and\nINVOKER.\nThese indicate that the required privileges must be held by\nthe user\nwho defined or invoked the view, respectively. The default\nSQL\nSECURITY value is DEFINER.\n \nIf a user value is given for the DEFINER clause, it should\nbe a MariaDB\naccount in \'user_name\'@\'host_name\' format (the same\nformat used in the\nGRANT statement). The user_name and host_name values both\nare\nrequired. The definer can also be given as CURRENT_USER or\nCURRENT_USER(). The default DEFINER value is the user who\nexecutes the\nCREATE VIEW statement. This is the same as specifying\nDEFINER =\nCURRENT_USER explicitly.\n \nIf you specify the DEFINER clause, these rules determine the\nlegal\nDEFINER user values:\nIf you do not have the SUPER privilege, the only legal user\nvalue is your own account, either specified literally or by\nusing CURRENT_USER. You cannot set the definer to some other\naccount.\nIf you have the SUPER privilege, you can specify any\nsyntactically legal account name. If the account does not\nactually exist, a warning is generated.\nIf the SQL SECURITY value is DEFINER but the definer account\ndoes not exist when the view is referenced, an error occurs.\n \nWithin a view definition, CURRENT_USER returns the view\'s\nDEFINER\nvalue by default. Before MySQL 5.1.12, and for views\ndefined with the SQL SECURITY INVOKER characteristic,\nCURRENT_USER\nreturns the account for the view\'s invoker. For information\nabout user\nauditing within views, see\nhttp://dev.mysql.com/doc/refman/5.1/en/account-activity-auditing.html.\n \nWithin a stored routine that is defined with the SQL\nSECURITY DEFINER\ncharacteristic, CURRENT_USER returns the routine\'s DEFINER\nvalue. This\nalso affects a view defined within such a program, if the\nview\ndefinition contains a DEFINER value of CURRENT_USER.\n \nView privileges are checked like this:\nAt view definition time, the view creator must have the\nprivileges needed to use the top-level objects accessed by\nthe view. For example, if the view definition refers to\ntable columns, the creator must have privileges for the\ncolumns, as described previously. If the definition refers\nto a stored function, only the privileges needed to invoke\nthe function can be checked. The privileges required when\nthe function runs can be checked only as it executes: For\ndifferent invocations of the function, different execution\npaths within the function might be taken.\nWhen a view is referenced, privileges for objects accessed\nby the view are checked against the privileges held by the\nview creator or invoker, depending on whether the SQL\nSECURITY characteristic is DEFINER or INVOKER, respectively.\nIf reference to a view causes execution of a stored\nfunction, privilege checking for statements executed within\nthe function depend on whether the function is defined with\na SQL SECURITY characteristic of DEFINER or INVOKER. If the\nsecurity characteristic is DEFINER, the function runs with\nthe privileges of its creator. If the characteristic is\nINVOKER, the function runs with the privileges determined by\nthe view\'s SQL SECURITY characteristic.\n \nMySQL until 5.1.1\n \nPrior to MySQL 5.1.2 (before the DEFINER and SQL SECURITY\nclauses were\nimplemented), privileges required for objects used in a view\nare\nchecked at view creation time.\n \nExample: A view might depend on a stored function, and that\nfunction\nmight invoke other stored routines. For example, the\nfollowing view\ninvokes a stored function f():\n \nCREATE VIEW v AS SELECT * FROM t WHERE t.id = f(t.name);\n \nSuppose that f() contains a statement such as this:\n \nIF name IS NULL then\n CALL p1();\nELSE\n CALL p2();\nEND IF;\n \nThe privileges required for executing statements within f()\nneed to be\nchecked when f() executes. This might mean that privileges\nare needed\nfor p1() or p2(), depending on the execution path within\nf(). Those\nprivileges must be checked at runtime, and the user who must\npossess\nthe privileges is determined by the SQL SECURITY values of\nthe view v\nand the function f().\n \nThe DEFINER and SQL SECURITY clauses for views are\nextensions to\nstandard SQL. In standard SQL, views are handled using the\nrules for\nSQL SECURITY INVOKER.\n \nIf you invoke a view that was created before MySQL 5.1.2, it\nis\ntreated as though it was created with a SQL SECURITY DEFINER\nclause\nand with a DEFINER value that is the same as your account.\nHowever,\nbecause the actual definer is unknown, MySQL issues a\nwarning. To make\nthe warning go away, it is sufficient to re-create the view\nso that\nthe view definition includes a DEFINER clause.\n \nThe optional ALGORITHM clause is an extension to standard\nSQL. It\naffects how MariaDB processes the view. ALGORITHM takes\nthree values:\nMERGE, TEMPTABLE, or UNDEFINED. The default algorithm is\nUNDEFINED if\nno ALGORITHM clause is present. See View Algorithms for more\ninformation.\n \nSome views are updatable. That is, you can use them in\nstatements such\nas UPDATE, DELETE, or INSERT to update the contents of the\nunderlying\ntable. For a view to be updatable, there must be a\none-to-one\nrelationship between the rows in the view and the rows in\nthe\nunderlying table. There are also certain other constructs\nthat make a\nview non-updatable. See Inserting and Updating with Views.\n \nWITH CHECK OPTION\n \nThe WITH CHECK OPTION clause can be given for an updatable\nview to\nprevent inserts or updates to rows except those for which\nthe WHERE\nclause in the select_statement is true.\n \nIn a WITH CHECK OPTION clause for an updatable view, the\nLOCAL and\nCASCADED keywords determine the scope of check testing when\nthe view\nis defined in terms of another view. The LOCAL keyword\nrestricts the\nCHECK OPTION only to the view being defined. CASCADED causes\nthe\nchecks for underlying views to be evaluated as well. When\nneither\nkeyword is given, the default is CASCADED.\n \nFor more information about updatable views and the WITH\nCHECK OPTION\nclause, see\nInserting and Updating with Views.\n \nIF NOT EXISTS\n \nThe IF NOT EXISTS clause was added in MariaDB 10.1.3\n \nWhen the IF NOT EXISTS clause is used, MariaDB will return a\nwarning instead of an error if the specified view already\nexists. Cannot be used together with the OR REPLACE clause.\n \nExamples\n-------- \nCREATE TABLE t (a INT, b INT) ENGINE = InnoDB;\n \nINSERT INTO t VALUES (1,1), (2,2), (3,3);\n \nCREATE VIEW v AS SELECT a, a*2 AS a2 FROM t;\n \nSELECT * FROM v;\n \n+------+------+\n| a | a2 |\n+------+------+\n| 1 | 2 |\n| 2 | 4 |\n| 3 | 6 |\n+------+------+\n \nOR REPLACE and IF NOT EXISTS:\n \nCREATE VIEW v AS SELECT a, a*2 AS a2 FROM t;\n \nERROR 1050 (42S01): Table \'v\' already exists\n \nCREATE OR REPLACE VIEW v AS SELECT a, a*2 AS a2 FROM t;\n \nQuery OK, 0 rows affected (0.04 sec)\n \nCREATE VIEW IF NOT EXISTS v AS SELECT a, a*2 AS a2 FROM t;\n \nQuery OK, 0 rows affected, 1 warning (0.01 sec)\n \nSHOW WARNINGS;\n \n+-------+------+--------------------------+\n| Level | Code | Message |\n+-------+------+--------------------------+\n| Note | 1050 | Table \'v\' already exists |\n+-------+------+--------------------------+\n \n\n\nURL: https://mariadb.com/kb/en/library/create-view/','','https://mariadb.com/kb/en/library/create-view/'); |