在MySQL中,如何获得所有外键约束指向特定表的列表?一个特定的专栏?这和Oracle的问题是一样的,但是是MySQL的问题。
当前回答
如果你还想获取外键列的名称:
SELECT i.TABLE_SCHEMA, i.TABLE_NAME,
i.CONSTRAINT_TYPE, i.CONSTRAINT_NAME,
k.COLUMN_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.TABLE_SCHEMA = '<TABLE_NAME>' AND i.CONSTRAINT_TYPE = 'FOREIGN KEY'
ORDER BY i.TABLE_NAME;
其他回答
方法列出fk(外键引用)的快速方法
KEY_COLUMN_USAGE view:
SELECT CONCAT( table_name, '.',
column_name, ' -> ',
referenced_table_name, '.',
referenced_column_name ) AS list_of_fks
FROM information_schema.KEY_COLUMN_USAGE
WHERE REFERENCED_TABLE_SCHEMA = (your schema name here)
AND REFERENCED_TABLE_NAME is not null
ORDER BY TABLE_NAME, COLUMN_NAME;
这个查询假设约束和所有引用和引用的表都在同一个模式中。
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来源:mysql官方手册。
查找包含特定外键(如employee_id)的所有表
SELECT DISTINCT TABLE_NAME
FROM INFORMATION_SCHEMA.COLUMNS
WHERE COLUMN_NAME IN ('employee_id')
AND TABLE_SCHEMA='table_name';
我提出的解决方案是脆弱的;它依赖于django的外键命名约定。
USE information_schema;
tee mysql_output
SELECT * FROM TABLE_CONSTRAINTS WHERE CONSTRAINT_TYPE = 'FOREIGN KEY' AND TABLE_SCHEMA = 'database_name';
notee
然后在壳层中,
grep 'refs_tablename_id' mysql_output
了解更新和删除行为通常是有帮助的,这是其他答案没有提供的。现在开始。
SELECT cu.table_name,
cu.column_name,
cu.constraint_name,
cu.referenced_table_name,
cu.referenced_column_name,
IF(rc.update_rule = 'NO ACTION', 'RESTRICT', rc.update_rule) AS update_rule,-- See: https://stackoverflow.com/a/1498015/2742117
IF(rc.delete_rule = 'NO ACTION', 'RESTRICT', rc.delete_rule) AS delete_rule -- See: https://stackoverflow.com/a/1498015/2742117
FROM information_schema.key_column_usage cu
INNER JOIN information_schema.referential_constraints rc ON rc.constraint_schema = cu.table_schema
AND rc.table_name = cu.table_name
AND rc.constraint_name = cu.constraint_name
WHERE cu.referenced_table_schema = '<your schema>'
AND cu.referenced_table_name = '<your table>';
如果你使用InnoDB并定义了FK,你可以查询information_schema数据库,例如:
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';