MDEV-9142 :Adding Constraint with no database reference

results in ERROR 1046 (3D000) at line 13: No database selected.

Use database from create table to foreign key database if
nothing else is given.

1 files changed, 25 insertions, 5 deletions

diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc
index a52d55b47e9..a3114aba7d3 100644
--- a/sql/sql_parse.cc
+++ b/sql/sql_parse.cc
@@ -5395,6 +5395,7 @@ bool check_global_access(THD *thd, ulong want_access, bool no_errors)
                                 temporary table flag)
   @param alter_info    [in]     Initial list of columns and indexes for the
                                 table to be created
+  @param create_db     [in]     Database of the created table
 
   @retval
    false  ok.
@@ -5403,7 +5404,8 @@ bool check_global_access(THD *thd, ulong want_access, bool no_errors)
 */
 bool check_fk_parent_table_access(THD *thd,
                                   HA_CREATE_INFO *create_info,
-                                  Alter_info *alter_info)
+                                  Alter_info *alter_info,
+                                  const char* create_db)
 {
   Key *key;
   List_iterator<Key> key_iterator(alter_info->key_list);
@@ -5443,10 +5445,28 @@ bool check_fk_parent_table_access(THD *thd,
           return true;
         }
       }
-      else if (thd->lex->copy_db_to(&db_name.str, &db_name.length))
-        return true;
       else
-        is_qualified_table_name= false;
+      {
+        if (!thd->db)
+        {
+          db_name.str= (char *) thd->memdup(create_db, strlen(create_db)+1);
+          db_name.length= strlen(create_db);
+          is_qualified_table_name= true;
+
+          if(create_db && check_db_name(&db_name))
+          {
+            my_error(ER_WRONG_DB_NAME, MYF(0), db_name.str);
+            return true;
+          }
+        }
+        else
+        {
+          if (thd->lex->copy_db_to(&db_name.str, &db_name.length))
+            return true;
+          else
+           is_qualified_table_name= false;
+        }
+      }
 
       // if lower_case_table_names is set then convert tablename to lower case.
       if (lower_case_table_names)
@@ -7462,7 +7482,7 @@ bool create_table_precheck(THD *thd, TABLE_LIST *tables,
       goto err;
   }
 
-  if (check_fk_parent_table_access(thd, &lex->create_info, &lex->alter_info))
+  if (check_fk_parent_table_access(thd, &lex->create_info, &lex->alter_info, create_table->db))
     goto err;
 
   error= FALSE;