如何查找所有具有引用特定表的外键的表。列和那些外键的值?

我有一个表，它的主键在其他几个表中作为外键引用。例如:

  CREATE TABLE `X` (
`X_id` int NOT NULL auto_increment,
`name` varchar(255) NOT NULL,
PRIMARY KEY  (`X_id`)
)
CREATE TABLE `Y` (
`Y_id` int(11) NOT NULL auto_increment,
`name` varchar(255) NOT NULL,
`X_id` int DEFAULT NULL,
PRIMARY KEY  (`Y_id`),
CONSTRAINT `Y_X` FOREIGN KEY (`X_id`) REFERENCES `X` (`X_id`)
)
CREATE TABLE `Z` (
`Z_id` int(11) NOT NULL auto_increment,
`name` varchar(255) NOT NULL,
`X_id` int DEFAULT NULL,
PRIMARY KEY  (`Z_id`),
CONSTRAINT `Z_X` FOREIGN KEY (`X_id`) REFERENCES `X` (`X_id`)
)

现在，我不知道数据库中有多少表包含X的外键，如表Y和z。是否有一个SQL查询，我可以使用返回:

  1. 具有X外键的表列表
  2. AND这些表中哪些外键中有值
183308 次浏览
小开

你可以在information_schema表中找到所有与模式相关的信息。

你可能想检查表REFERENTIAL_CONSTRAINTS和KEY_COLUMN_USAGE。前者告诉你哪些表被其他人引用;后者会告诉你他们的领域是如何相关的。

小开

给你:

SELECT *
FROM
information_schema.KEY_COLUMN_USAGE
WHERE
REFERENCED_TABLE_NAME = 'X'
AND REFERENCED_COLUMN_NAME = 'X_id';

如果你有多个具有相似表/列名的数据库，你可能也希望将查询限制在一个特定的数据库:

SELECT *
FROM
information_schema.KEY_COLUMN_USAGE
WHERE
REFERENCED_TABLE_NAME = 'X'
AND REFERENCED_COLUMN_NAME = 'X_id'
AND TABLE_SCHEMA = 'your_database_name';
小开

MySQL 5.5参考手册:InnoDB和外键约束

SELECT
ke.REFERENCED_TABLE_SCHEMA parentSchema,
ke.referenced_table_name parentTable,
ke.REFERENCED_COLUMN_NAME parentColumnName,
ke.TABLE_SCHEMA ChildSchema,
ke.table_name childTable,
ke.COLUMN_NAME ChildColumnName
FROM
information_schema.KEY_COLUMN_USAGE ke
WHERE
ke.referenced_table_name IS NOT NULL
AND ke.REFERENCED_COLUMN_NAME = 'ci_id' ## Find Foreign Keys linked to this Primary Key
ORDER BY
ke.referenced_table_name;
小开

这个解决方案不仅会显示所有的关系，还会显示约束的名称，这在某些情况下是必需的(例如drop constraint):

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;

如果您想检查特定数据库中的表，请添加以下内容:

AND table_schema = 'database_name';
小开

我写了一点bash在线，你可以把它写到一个脚本中来得到一个友好的输出:

mysql_references_to:

mysql -uUSER -pPASS -A DB_NAME -se "USE information_schema; SELECT * FROM KEY_COLUMN_USAGE WHERE REFERENCED_TABLE_NAME = '$1' AND REFERENCED_COLUMN_NAME = 'id'\G" | sed 's/^[ \t]*//;s/[ \t]*$//' |egrep "\<TABLE_NAME|\<COLUMN_NAME" |sed 's/TABLE_NAME: /./g' |sed 's/COLUMN_NAME: //g' | paste -sd "," -| tr '.' '\n' |sed 's/,$//' |sed 's/,/./'

所以执行:mysql_references_to transaccion(其中transaccion是一个随机表名)给出如下输出:

carrito_transaccion.transaccion_id
comanda_detalle.transaccion_id
comanda_detalle_devolucion.transaccion_positiva_id
comanda_detalle_devolucion.transaccion_negativa_id
comanda_transaccion.transaccion_id
cuenta_operacion.transaccion_id
...
小开

列出一个db中的所有外键，包括描述

    SELECT
i1.CONSTRAINT_NAME, i1.TABLE_NAME,i1.COLUMN_NAME,
i1.REFERENCED_TABLE_SCHEMA,i1.REFERENCED_TABLE_NAME, i1.REFERENCED_COLUMN_NAME,
i2.UPDATE_RULE, i2.DELETE_RULE
FROM
information_schema.KEY_COLUMN_USAGE AS i1
INNER JOIN
information_schema.REFERENTIAL_CONSTRAINTS AS i2
ON i1.CONSTRAINT_NAME = i2.CONSTRAINT_NAME
WHERE i1.REFERENCED_TABLE_NAME IS NOT NULL
AND  i1.TABLE_SCHEMA  ='db_name';

限制到表中的特定列

AND i1.table_name = 'target_tb_name' AND i1.column_name = 'target_col_name'
小开
< p >简单:< br > 1. 打开phpMyAdmin < br > 2. 在左侧单击数据库名称
3.在右上角找到"Designer"选项卡

所有的约束都将显示在那里。

小开

SELECT TABLE_NAME, COLUMN_NAME . 从information_schema。KEY_COLUMN_USAGE WHERE CONSTRAINT_SCHEMA LIKE 'your_database' 和TABLE_SCHEMA LIKE 'your_database' 和REFERENCED_TABLE_SCHEMA LIKE 'your_database' 和REFERENCED_TABLE_NAME LIKE 'your_table' AND REFERENCED_COLUMN_NAME LIKE 'your_column';

小开

2022年06

基于@Panayotis的回答，但结构更好。

这将列出多个表中的所有约束。
我还包含了TABLE_SCHEMA来显示数据库名称

SQL

SELECT
TABLE_SCHEMA AS 'Database',
TABLE_NAME AS t1,
REFERENCED_TABLE_NAME AS 't2 (reference table)',
COLUMN_NAME AS 't1 column',
REFERENCED_COLUMN_NAME AS 't2 column (reference table)',
CONSTRAINT_NAME AS 't1 (constrain name)'
FROM
information_schema.key_column_usage
WHERE
referenced_table_name IS NOT NULL

输出

+------------+------------+---------------------+---------------+----------------------------+------------------------+
| Database   | t1         | t2 (reference table) | t1 column     | t2 column (reference table) | t1 (constrain name)    |
+============+============+=====================+===============+============================+========================+
| foobar     | credential | userdetail          | userdetail_fk | id                         | credentialUserdetailFk |
+------------+------------+---------------------+---------------+----------------------------+------------------------+
| foobar     | loginlog   | userdetail          | userdetail_fk | id                         | loginlogUserdetailFk   |
+------------+------------+---------------------+---------------+----------------------------+------------------------+
+ client     | userdetail | client              | client_fk     | id                         | userdetailClientFk     |
+------------+------------+---------------------+---------------+----------------------------+------------------------+

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