information_schema系统表——TABLE_CONSTRAINTS

表约束信息

INFORMATION_SCHEMA NameSHOW NameRemarksCONSTRAINT_CATALOG defCONSTRAINT_SCHEMA  CONSTRAINT_NAME  TABLE_SCHEMA  TABLE_NAME  CONSTRAINT_TYPE  

Notes:

• The CONSTRAINT_TYPE value can be UNIQUE, PRIMARY KEY, or FOREIGN KEY.

• The UNIQUE and PRIMARY KEY information is about the same as what you get from the Key_name field in the output from SHOW INDEX when the Non_unique field is 0.

• The CONSTRAINT_TYPE column can contain one of these values: UNIQUE, PRIMARY KEY, FOREIGN KEY, CHECK. This is a CHAR (not ENUM) column. The CHECK value is not available until we support CHECK.

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