INFORMATION_SCHEMA.TABLE_CONSTRAINTS是一个系统表,它存储了关于数据库中所有表的约束信息。这个表是SQL标准的一部分,大多数关系型数据库管理系统(如MySQL、PostgreSQL、SQL Server等)都提供了类似的表来存储元数据信息。 表结构 以下是INFORMATION_SCHEMA.TABLE_CONSTRAINTS表的一些主要列及
TheTABLE_CONSTRAINTStable describes which tables have constraints. TheTABLE_CONSTRAINTStable has these columns: CONSTRAINT_CATALOG The name of the catalog to which the constraint belongs. This value is alwaysdef. CONSTRAINT_SCHEMA The name of the schema (database) to which the constraint belongs. ...
ALTERTABLEtable_nameADDCOLUMNcolumn_name column_type [ column_constraints ]; column_name:新列的名称。 column_type:新列的数据类型。 column_constraints:列的约束条件(如NOT NULL、DEFAULT)。 示例: 向employees表中添加一个date_of_birth列: ALTERTABLEemployeesADDCOLUMNdate_of_birthDATE; 要添加一个带有默...
The possible values are CASCADE, SET NULL, SET DEFAULT, RESTRICT, NO ACTION. TABLE_NAME The name of the table. This value is the same as in the TABLE_CONSTRAINTS table. REFERENCED_TABLE_NAME The name of the table referenced by the constraint. ...
PRIMARY KEY (TABLE_C_TABLE_D_ID, TABLE_C_ID)); ALTER TABLE TABLE_D ADD ( FOREIGN KEY (TABLE_C_ID) REFERENCES TABLE_C(TABLE_C_ID)); When I query table_constraints on my TABLE_D it shows the primary key but not the foreign key. What am I doing wrong?Navigate...
MySQL Error [1109]: "Unknown table 'referential_constraints' in information_schema" Backtrace for: #<SB-THREAD:THREAD "main thread" RUNNING {1008B846C3}> 0: ((LAMBDA NIL :IN SB-DEBUG::FUNCALL-WITH-DEBUG-IO-SYNTAX)) 1: (SB-IMPL::CALL-WITH-SANE-IO-SYNTAX #<CLOSURE (LAMBDA NIL :IN ...
SQL supports foreign keys, which let you cross-reference related data across tables, and foreign key constraints, which help keep this spread-out data consistent. The essential syntax for a foreign key constraint definition in a CREATE TABLE or ALTER TABLE statement looks like this: ...
true for names of cursors, conditions, procedures, functions, savepoints, stored routine parameters, stored program local variables, and plugins. It is not true for names of columns, constraints, databases, partitions, statements prepared withPREPARE, tables, triggers, users, and user-defined ...
Bug #16614 SHOW CREATE TABLE does not show constraints for InnoDB tables Submitted: 18 Jan 2006 19:15Modified: 7 Jul 2006 0:32 Reporter: Mark Matthews Email Updates: Status: Closed Impact on me: None Category: MySQL Server: Information schemaSeverity: S2 (Serious) Version: 5.1.5OS: ...
How to get table constraints David Baker June 26, 2007 08:14AM Re: How to get table constraints Roland Bouman August 01, 2007 06:35PM Sorry, you can't reply to this topic. It has been closed.Content reproduced on this site is the property of the respective copyright holders. It is...