[MySQL]MySQL数据库中如何使用SQL语句查看表或者列的所有外键?
问题描述
如题,[MySQL]MySQL数据库中如何使用SQL语句查看表或者列的所有外键?
方案一
查看一张表的所有外键:
SELECT
TABLE_NAME,COLUMN_NAME,CONSTRAINT_NAME, REFERENCED_TABLE_NAME,REFERENCED_COLUMN_NAME
FROM
INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE
REFERENCED_TABLE_SCHEMA = '<database>' AND
REFERENCED_TABLE_NAME = '<table>';
查看一个列的所有外键:
SELECT
TABLE_NAME,COLUMN_NAME,CONSTRAINT_NAME, REFERENCED_TABLE_NAME,REFERENCED_COLUMN_NAME
FROM
INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE
REFERENCED_TABLE_SCHEMA = '<database>' AND
REFERENCED_COLUMN_NAME = '<column>';
方案二
如果使用InnoDB引擎并且定义了外键:
SELECT * FROM information_schema.TABLE_CONSTRAINTS
WHERE information_schema.TABLE_CONSTRAINTS.CONSTRAINT_TYPE = 'FOREIGN KEY'
AND information_schema.TABLE_CONSTRAINTS.TABLE_SCHEMA = 'myschema'
AND information_schema.TABLE_CONSTRAINTS.TABLE_NAME = 'mytable';
方案三
查看一张表的所有外键:
USE '<yourschema>';
SELECT i.TABLE_NAME, i.CONSTRAINT_TYPE, i.CONSTRAINT_NAME, k.REFERENCED_TABLE_NAME, k.REFERENCED_COLUMN_NAME
FROM information_schema.TABLE_CONSTRAINTS i
LEFT JOIN information_schema.KEY_COLUMN_USAGE k ON i.CONSTRAINT_NAME = k.CONSTRAINT_NAME
WHERE i.CONSTRAINT_TYPE = 'FOREIGN KEY'
AND i.TABLE_SCHEMA = DATABASE()
AND i.TABLE_NAME = '<yourtable>';
查看框架(schema)中所有表的所有外键:
USE '<yourschema>';
SELECT i.TABLE_NAME, i.CONSTRAINT_TYPE, i.CONSTRAINT_NAME, k.REFERENCED_TABLE_NAME, k.REFERENCED_COLUMN_NAME
FROM information_schema.TABLE_CONSTRAINTS i
LEFT JOIN information_schema.KEY_COLUMN_USAGE k ON i.CONSTRAINT_NAME = k.CONSTRAINT_NAME
WHERE i.CONSTRAINT_TYPE = 'FOREIGN KEY'
AND i.TABLE_SCHEMA = DATABASE();
查看数据库中所有外键:
SELECT i.TABLE_SCHEMA, i.TABLE_NAME, i.CONSTRAINT_TYPE, i.CONSTRAINT_NAME, k.REFERENCED_TABLE_NAME, k.REFERENCED_COLUMN_NAME
FROM information_schema.TABLE_CONSTRAINTS i
LEFT JOIN information_schema.KEY_COLUMN_USAGE k ON i.CONSTRAINT_NAME = k.CONSTRAINT_NAME
WHERE i.CONSTRAINT_TYPE = 'FOREIGN KEY';
方案四
查看数据所有关系及约束等集合
select
concat(table_name, '.', column_name) as 'foreign key',
concat(referenced_table_name, '.', referenced_column_name) as 'references',
constraint_name as 'constraint name'
from
information_schema.key_column_usage
where
referenced_table_name is not null;
如果想要查看指定的数据库和数据表,则:
select
concat(table_name, '.', column_name) as 'foreign key',
concat(referenced_table_name, '.', referenced_column_name) as 'references',
constraint_name as 'constraint name'
from
information_schema.key_column_usage
where
referenced_table_name is not null
and table_schema = 'database_name';
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