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:

具有X外键的表列表 AND这些表中哪些外键中有值

当前回答

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';

2013-09-16 10:35:10

其他回答

选择table_name, column_name 从information_schema。KEY_COLUMN_USAGE WHERE CONSTRAINT_SCHEMA LIKE 'your_database' 和TABLE_SCHEMA LIKE 'your_database' AND REFERENCED_TABLE_SCHEMA LIKE 'your_database' 和REFERENCED_TABLE_NAME LIKE 'your_table' AND REFERENCED_COLUMN_NAME LIKE 'your_column';

2021-04-01 20:59:35

06 2022

基于@Panayotis的回答，但结构更好。

这将从多个表中列出所有约束。我还包含了TABLE_SCHEMA以显示数据库名称。

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     |
+------------+------------+---------------------+---------------+----------------------------+------------------------+

2022-06-03 03:12:37

您可以在明智地命名为information_schema表中找到所有与模式相关的信息。

您可能需要检查REFERENTIAL_CONSTRAINTS和KEY_COLUMN_USAGE表。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。

2009-04-30 13:57:38

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';

2009-07-15 19:27:30

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;

2010-07-22 17:23:50

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?

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