MDEV-7563 Support CHECK constraint as in (or close to) SQL Standard

MDEV-10134 Add full support for DEFAULT

- Added support for using tables with MySQL 5.7 virtual fields,
  including MySQL 5.7 syntax
- Better error messages also for old cases
- CREATE ... SELECT now also updates timestamp columns
- Blob can now have default values
- Added new system variable "check_constraint_checks", to turn of
  CHECK constraint checking if needed.
- Removed some engine independent tests in suite vcol to only test myisam
- Moved some tests from 'include' to 't'. Should some day be done for all tests.
- FRM version increased to 11 if one uses virtual fields or constraints
- Changed to use a bitmap to check if a field has got a value, instead of
  setting HAS_EXPLICIT_VALUE bit in field flags
- Expressions can now be up to 65K in total
- Ensure we are not refering to uninitialized fields when handling virtual fields or defaults
- Changed check_vcol_func_processor() to return a bitmap of used types
- Had to change some functions that calculated cached value in fix_fields to do
  this in val() or getdate() instead.
- store_now_in_TIME() now takes a THD argument
- fill_record() now updates default values
- Add a lookahead for NOT NULL, to be able to handle DEFAULT 1+1 NOT NULL
- Automatically generate a name for constraints that doesn't have a name
- Added support for ALTER TABLE DROP CONSTRAINT
- Ensure that partition functions register virtual fields used. This fixes
  some bugs when using virtual fields in a partitioning function

1 files changed, 33 insertions, 31 deletions

diff --git a/sql/item_strfunc.h b/sql/item_strfunc.h
index 72cdf06adde..3675707db41 100644
--- a/sql/item_strfunc.h
+++ b/sql/item_strfunc.h
@@ -517,9 +517,9 @@ public:
   String *val_str(String *);
   void fix_length_and_dec() { maybe_null=1; max_length = 13; }
   const char *func_name() const { return "encrypt"; }
-  bool check_vcol_func_processor(uchar *int_arg) 
+  bool check_vcol_func_processor(uchar *arg)
   {
-    return trace_unsupported_by_check_vcol_func_processor(func_name());
+    return FALSE;
   }
 };
 
@@ -572,10 +572,10 @@ public:
     call
   */
   virtual const char *fully_qualified_func_name() const = 0;
-  bool check_vcol_func_processor(uchar *int_arg) 
+  bool check_vcol_func_processor(uchar *arg)
   {
-    return trace_unsupported_by_check_vcol_func_processor(
-                                           fully_qualified_func_name());
+    return mark_unsupported_function(fully_qualified_func_name(), arg,
+                                     VCOL_NON_DETERMINISTIC);
   }
 };
 
@@ -598,19 +598,14 @@ public:
 class Item_func_user :public Item_func_sysconst
 {
 protected:
-  bool init (const char *user, const char *host);
+  query_id_t last_query_id;
+  bool init(THD *thd, const char *user, const char *host);
 
 public:
-  Item_func_user(THD *thd): Item_func_sysconst(thd)
-  {
-    str_value.set("", 0, system_charset_info);
-  }
-  String *val_str(String *)
-  {
-    DBUG_ASSERT(fixed == 1);
-    return (null_value ? 0 : &str_value);
-  }
-  bool fix_fields(THD *thd, Item **ref);
+  Item_func_user(THD *thd): Item_func_sysconst(thd), last_query_id(0)
+  {}
+
+  String *val_str(String *);
   void fix_length_and_dec()
   {
     max_length= (username_char_length +
@@ -618,10 +613,6 @@ public:
   }
   const char *func_name() const { return "user"; }
   const char *fully_qualified_func_name() const { return "user()"; }
-  int save_in_field(Field *field, bool no_conversions)
-  {
-    return save_str_value_in_field(field, &str_value);
-  }
 };
 
 
@@ -632,9 +623,15 @@ class Item_func_current_user :public Item_func_user
 public:
   Item_func_current_user(THD *thd, Name_resolution_context *context_arg):
     Item_func_user(thd), context(context_arg) {}
-  bool fix_fields(THD *thd, Item **ref);
+  String *val_str(String *);
   const char *func_name() const { return "current_user"; }
   const char *fully_qualified_func_name() const { return "current_user()"; }
+  /* This is because of the stored Name_resolution_context */
+  bool check_vcol_func_processor(uchar *arg)
+  {
+    return mark_unsupported_function(fully_qualified_func_name(), arg,
+                                     VCOL_IMPOSSIBLE);
+  }
 };
 
 
@@ -647,15 +644,20 @@ public:
     Item_func_sysconst(thd), context(context_arg) {}
   bool fix_fields(THD *thd, Item **ref);
   void fix_length_and_dec()
-  { max_length= username_char_length * SYSTEM_CHARSET_MBMAXLEN; }
-  int save_in_field(Field *field, bool no_conversions)
-  { return save_str_value_in_field(field, &str_value); }
+  {
+    max_length= username_char_length * SYSTEM_CHARSET_MBMAXLEN;
+    maybe_null=1;
+  }
+  bool init(THD *thd);
+  int save_in_field(Field *field, bool no_conversions);
   const char *func_name() const { return "current_role"; }
   const char *fully_qualified_func_name() const { return "current_role()"; }
-  String *val_str(String *)
+  String *val_str(String *);
+  /* This is because of the stored Name_resolution_context */
+  bool check_vcol_func_processor(uchar *arg)
   {
-    DBUG_ASSERT(fixed == 1);
-    return (null_value ? 0 : &str_value);
+    return mark_unsupported_function(fully_qualified_func_name(), arg,
+                                     VCOL_IMPOSSIBLE);
   }
 };
 
@@ -916,9 +918,9 @@ public:
     maybe_null=1;
     max_length=MAX_BLOB_WIDTH;
   }
-  bool check_vcol_func_processor(uchar *int_arg) 
+  bool check_vcol_func_processor(uchar *arg)
   {
-    return trace_unsupported_by_check_vcol_func_processor(func_name());
+    return mark_unsupported_function(func_name(), arg, VCOL_IMPOSSIBLE);
   }
 };
 
@@ -1183,9 +1185,9 @@ public:
   }
   const char *func_name() const{ return "uuid"; }
   String *val_str(String *);
-  bool check_vcol_func_processor(uchar *int_arg) 
+  bool check_vcol_func_processor(uchar *arg)
   {
-    return trace_unsupported_by_check_vcol_func_processor(func_name());
+    return mark_unsupported_function(func_name(), arg, VCOL_NON_DETERMINISTIC);
   }
 };