如何找出什么FOREIGN KEY约束引用SQL Server中的表？

我正在尝试删除表，但收到以下消息：

消息3726，级别16，状态1，第3行
无法删除对象'dbo.UserProfile'，因为它是由FOREIGN KEY约束引用的。
消息2714，级别16，状态6，第2
行在数据库中已经有一个名为“ UserProfile”的对象。

我环顾了SQL Server Management Studio，但找不到约束。如何找出外键约束？

这里是：

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。

根据注释建议进行编辑，以使用sys.tables代替通用sys.objects。谢谢，marc_s

另一种方法是检查结果

sp_help 'TableName'

（或仅突出显示加引号的TableName和pres ALT + F1）

随着时间的流逝，我只是决定完善自己的答案。以下是sp_help提供的结果的屏幕截图。A在此示例中使用了AdventureWorksDW2012 DB。那里有很多很好的信息，而我们正在寻找的最终是-以绿色突出显示：

试试这个

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')

我发现此答案非常简单，并针对我所需的技巧进行了欺骗：https : //stackoverflow.com/a/12956348/652519

来自链接的摘要，请使用以下查询：

EXEC sp_fkeys 'TableName'

快速简单。我能够很快找到所有外键表，相应的列和15个表的外键名称。

如下@mdisibio所述，这是指向详细说明可以使用的不同参数的文档的链接：https : //docs.microsoft.com/zh-cn/sql/relational-databases/system-stored-procedures/sp- fkeys-transact-sql

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

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

如果要在对象浏览器窗口中通过SSMS进行操作，请右键单击要删除的对象，然后查看依赖项。

这是在所有数据库中查找外键关系的最佳方法。

exec sp_helpconstraint 'Table Name'

还有另一种方法

select * from INFORMATION_SCHEMA.KEY_COLUMN_USAGE where TABLE_NAME='Table Name'
--and left(CONSTRAINT_NAME,2)='FK'(If you want single key)

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;

-以下内容可能会为您提供更多所需的信息：

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

您还可以Foreign Keys通过适应@LittleSweetSeas答案来返回有关的所有信息：

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

在SQL Server Management Studio中，您可以右键单击对象资源管理器中的表，然后选择“查看依赖项”。这将为您提供一个良好的起点。它显示了引用该表的表，视图和过程。

请尝试以下查询。

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>);

这将提供constraint_name，将要引用的column_names和将取决于约束的表。

您可以使用此查询来显示Foreign key常量：

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-数据库内/

获得最简单的方法Primary Key，并Foreign Key为表：

/*  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'

在对象资源管理器中，展开表，然后展开“键”：