如何找出FOREIGN KEY约束引用SQL Server中的表？


How can I find out what FOREIGN KEY constraint references a table in SQL Server?

我想删除一个表但收到以下消息：

Msg 3726, Level 16, State 1, Line 3
Could not drop object 'dbo.UserProfile' because it is referenced by a FOREIGN KEY constraint.
Msg 2714, Level 16, State 6, Line 2
There is already an object named 'UserProfile' in the database.

我浏览了SQL Server Management Studio但我无法找到约束。 如何找出外键约束？

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这里是：

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SELECT
   OBJECT_NAME(f.parent_object_id) TableName,
   COL_NAME(fc.parent_object_id,fc.parent_column_id) ColName
FROM
   sys.foreign_keys AS f
INNER JOIN
   sys.foreign_key_columns AS fc
      ON f.OBJECT_ID = fc.constraint_object_id
INNER JOIN
   sys.tables t
      ON t.OBJECT_ID = fc.referenced_object_id
WHERE
   OBJECT_NAME (f.referenced_object_id) = 'YourTableName'

这样，您将获得引用表和列名称。

根据评论建议编辑使用sys.tables而不是通用sys.objects。
谢谢，marc_s

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另一种方法是检查结果

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sp_help 'TableName'

(或只是突出显示引用的TableName和pres ALT + F1)

随着时间的推移，我决定改进我的答案。下面是sp_help提供的结果的屏幕截图。 A在此示例中使用了AdventureWorksDW2012数据库。那里有很多好的信息，我们正在寻找的是最后的 - 以绿色突出显示：

enter image description here

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试试这个

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SELECT
  object_name(parent_object_id) ParentTableName,
  object_name(referenced_object_id) RefTableName,
  name
FROM sys.foreign_keys
WHERE parent_object_id = object_id('Tablename')
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我发现这个答案非常简单，并根据我的需要做了诀窍：https：//stackoverflow.com/a/12956348/652519

链接摘要，使用此查询：

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EXEC sp_fkeys 'TableName'

快速而简单。我能够很快找到15个表的所有外键表，各自的列和外键名。

正如@mdisibio在下面提到的，这里是文档的链接，详细说明了可以使用的不同参数：https：//docs.microsoft.com/en-us/sql/relational-databases/system-stored-procedures/sp- fkeys-的Transact-SQL

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我正在使用此脚本查找与外键相关的所有详细信息。
我正在使用INFORMATION.SCHEMA。
下面是一个SQL脚本：

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SELECT
    ccu.table_name AS SourceTable
    ,ccu.constraint_name AS SourceConstraint
    ,ccu.column_name AS SourceColumn
    ,kcu.table_name AS TargetTable
    ,kcu.column_name AS TargetColumn
FROM INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE ccu
    INNER JOIN INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS rc
        ON ccu.CONSTRAINT_NAME = rc.CONSTRAINT_NAME
    INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE kcu
        ON kcu.CONSTRAINT_NAME = rc.UNIQUE_CONSTRAINT_NAME  
ORDER BY ccu.table_name
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这是在所有数据库中找出外键关系的最佳方法。

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EXEC sp_helpconstraint 'Table Name'

还有一种方式

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SELECT * FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE WHERE TABLE_NAME='Table Name'
--and left(CONSTRAINT_NAME,2)='FK'(If you want single key)
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如果要在对象资源管理器窗口中通过SSMS，请右键单击要删除的对象，然后查看依赖项。

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SELECT
    obj.name      AS FK_NAME,
    sch.name      AS [schema_name],
    tab1.name     AS [TABLE],
    col1.name     AS [COLUMN],
    tab2.name     AS [referenced_table],
    col2.name     AS [referenced_column]
FROM
     sys.foreign_key_columns fkc
INNER JOIN sys.objects obj
    ON obj.object_id = fkc.constraint_object_id
INNER JOIN sys.tables tab1
    ON tab1.object_id = fkc.parent_object_id
INNER JOIN sys.schemas sch
    ON tab1.schema_id = sch.schema_id
INNER JOIN sys.columns col1
    ON col1.column_id = parent_column_id AND col1.object_id = tab1.object_id
INNER JOIN sys.tables tab2
    ON tab2.object_id = fkc.referenced_object_id
INNER JOIN sys.columns col2
    ON col2.column_id = referenced_column_id
        AND col2.object_id =  tab2.object_id;
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在SQL Server Management Studio中，您只需右键单击中的表即可
对象资源管理器并选择"查看依赖项"。这会给你一个
良好的起点。它显示了引用的表，视图和过程
桌子。

您还可以通过调整@LittleSweetSeas答案来返回有关Foreign Keys的所有信息：

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SELECT
   OBJECT_NAME(f.parent_object_id) ConsTable,
   OBJECT_NAME (f.referenced_object_id) refTable,
   COL_NAME(fc.parent_object_id,fc.parent_column_id) ColName
FROM
   sys.foreign_keys AS f
INNER JOIN
   sys.foreign_key_columns AS fc
      ON f.OBJECT_ID = fc.constraint_object_id
INNER JOIN
   sys.tables t
      ON t.OBJECT_ID = fc.referenced_object_id
ORDER BY
ConsTable

- 以下内容可能会为您提供更多您想要的内容：

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CREATE PROCEDURE spShowRelationShips
(
    @TABLE VARCHAR(250) = NULL,
    @RelatedTable VARCHAR(250) = NULL
)
AS
BEGIN
    IF @TABLE IS NULL AND @RelatedTable IS NULL
        SELECT  object_name(k.constraint_object_id) ForeginKeyName,
                object_name(k.Parent_Object_id) TableName,
                object_name(k.referenced_object_id) RelatedTable,
                c.Name RelatedColumnName,  
                object_name(rc.object_id) + '.' + rc.name RelatedKeyField
        FROM sys.foreign_key_columns k
        LEFT JOIN sys.columns c ON object_name(c.object_id) = object_name(k.Parent_Object_id) AND c.column_id = k.parent_column_id
        LEFT JOIN sys.columns rc ON object_name(rc.object_id) = object_name(k.referenced_object_id) AND rc.column_id = k.referenced_column_id
        ORDER BY 2,3

    IF @TABLE IS NOT NULL AND @RelatedTable IS NULL
        SELECT  object_name(k.constraint_object_id) ForeginKeyName,
                object_name(k.Parent_Object_id) TableName,
                object_name(k.referenced_object_id) RelatedTable,
                c.Name RelatedColumnName,  
                object_name(rc.object_id) + '.' + rc.name RelatedKeyField
        FROM sys.foreign_key_columns k
        LEFT JOIN sys.columns c ON object_name(c.object_id) = object_name(k.Parent_Object_id) AND c.column_id = k.parent_column_id
        LEFT JOIN sys.columns rc ON object_name(rc.object_id) = object_name(k.referenced_object_id) AND rc.column_id = k.referenced_column_id
        WHERE object_name(k.Parent_Object_id) =@TABLE
        ORDER BY 2,3

    IF @TABLE IS NULL AND @RelatedTable IS NOT NULL
        SELECT  object_name(k.constraint_object_id) ForeginKeyName,
                object_name(k.Parent_Object_id) TableName,
                object_name(k.referenced_object_id) RelatedTable,
                c.Name RelatedColumnName,  
                object_name(rc.object_id) + '.' + rc.name RelatedKeyField
        FROM sys.foreign_key_columns k
        LEFT JOIN sys.columns c ON object_name(c.object_id) = object_name(k.Parent_Object_id) AND c.column_id = k.parent_column_id
        LEFT JOIN sys.columns rc ON object_name(rc.object_id) = object_name(k.referenced_object_id) AND rc.column_id = k.referenced_column_id
        WHERE object_name(k.referenced_object_id) =@RelatedTable
        ORDER BY 2,3



END

获取表的Primary Key和Foreign key的最简单方法是：

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/*  Get primary key and foreign key for a table */
USE DatabaseName;

SELECT CONSTRAINT_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE CONSTRAINT_NAME LIKE 'PK%' AND
TABLE_NAME = 'TableName'

SELECT CONSTRAINT_NAME FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE
WHERE CONSTRAINT_NAME LIKE 'FK%' AND
TABLE_NAME = 'TableName'

您可以使用此查询来显示Foreign key constaraints：

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SELECT
K_Table = FK.TABLE_NAME,
FK_Column = CU.COLUMN_NAME,
PK_Table = PK.TABLE_NAME,
PK_Column = PT.COLUMN_NAME,
Constraint_Name = C.CONSTRAINT_NAME
FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS C
INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS FK ON C.CONSTRAINT_NAME = FK.CONSTRAINT_NAME
INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS PK ON C.UNIQUE_CONSTRAINT_NAME = PK.CONSTRAINT_NAME
INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE CU ON C.CONSTRAINT_NAME = CU.CONSTRAINT_NAME
INNER JOIN (
SELECT i1.TABLE_NAME, i2.COLUMN_NAME
FROM INFORMATION_SCHEMA.TABLE_CONSTRAINTS i1
INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE i2 ON i1.CONSTRAINT_NAME = i2.CONSTRAINT_NAME
WHERE i1.CONSTRAINT_TYPE = 'PRIMARY KEY'
) PT ON PT.TABLE_NAME = PK.TABLE_NAME
---- optional:
ORDER BY
1,2,3,4
WHERE PK.TABLE_NAME='YourTable'

取自http://blog.sqlauthority.com/2006/11/01/sql-server-query-to-display-foreign-key-relationships-and-name-of-the-constraint-for-each-table-在数据库/

尝试以下查询。

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SELECT object_name(sfc.constraint_object_id) AS constraint_name,
       OBJECT_Name(parent_object_id) AS TABLE_NAME ,
       ac1.name AS table_column_name,
       OBJECT_name(referenced_object_id) AS reference_table_name,      
       ac2.name AS reference_column_name
FROM  sys.foreign_key_columns sfc
JOIN sys.all_columns ac1 ON (ac1.object_id=sfc.parent_object_id AND ac1.column_id=sfc.parent_column_id)
JOIN sys.all_columns ac2 ON (ac2.object_id=sfc.referenced_object_id AND ac2.column_id=sfc.referenced_column_id)
WHERE sfc.parent_object_id=OBJECT_ID(<main TABLE name>);

这将给出将要引用的constraint_name，column_names以及将依赖于约束的表。