SELECT
OBJECT_NAME(parent_object_id) 'Parent table',
c.NAME 'Parent column name',
OBJECT_NAME(referenced_object_id) 'Referenced table',
cref.NAME 'Referenced column name'
FROM 
sys.foreign_key_columns fkc 
INNER JOIN 
sys.columns c 
   ON fkc.parent_column_id = c.column_id 
      AND fkc.parent_object_id = c.object_id
INNER JOIN 
sys.columns cref 
   ON fkc.referenced_column_id = cref.column_id 
      AND fkc.referenced_object_id = cref.object_id  where   OBJECT_NAME(parent_object_id) = 'tablename'

如果你想获得所有表的外键关系，排除where子句，否则写你的tablename而不是tablename

不知道为什么没有人建议，但我使用sp_fkeys查询给定表的外键:

EXEC sp_fkeys 'TableName'

你也可以指定模式:

EXEC sp_fkeys @pktable_name = 'TableName', @pktable_owner = 'dbo'

在没有指定模式的情况下，文档声明如下:

如果没有指定pktable_owner，则默认表可见性规则 的基础DBMS应用程序。 在SQL Server中，如果当前用户拥有一个具有指定 Name，返回该表的列。如果pktable_owner不是 且当前用户不拥有具有指定属性的表 Pktable_name时，该过程查找具有指定 由数据库所有者拥有的Pktable_name。如果存在，那张桌子就是 返回列。

你可以通过以下查询找到:

 SELECT OBJECT_NAME (FK.referenced_object_id) 'Referenced Table', 
      OBJECT_NAME(FK.parent_object_id) 'Referring Table', FK.name 'Foreign Key', 
      COL_NAME(FK.referenced_object_id, FKC.referenced_column_id) 'Referenced Column',
      COL_NAME(FK.parent_object_id,FKC.parent_column_id) 'Referring Column'
     FROM sys.foreign_keys AS FK
             INNER JOIN sys.foreign_key_columns AS FKC 
                 ON FKC.constraint_object_id = FK.OBJECT_ID
     WHERE OBJECT_NAME (FK.referenced_object_id) = 'YourTableName'
     AND COL_NAME(FK.referenced_object_id, FKC.referenced_column_id) = 'YourColumnName'
     order by  OBJECT_NAME(FK.parent_object_id)

这个答案建立在sp_fkeys的基础上，但格式化类似于sp_fkeys，适用于多个列并列出它们的顺序。

SELECT fk_obj.name    AS FK_NAME,
       pk_schema.name AS PKTABLE_OWNER,
       pk_table.name  AS PKTABLE_NAME,
       pk_column.name AS PKCOLUMN_NAME,
       fk_schema.name AS FKTABLE_OWNER,
       fk_table.name  AS FKTABLE_NAME,
       fk_column.name AS FKCOLUMN_NAME,
       ROW_NUMBER() over (
           PARTITION BY fk_obj.name, fk_schema.name
           ORDER BY fkc.constraint_column_id
           )          AS KEY_SEQ
FROM sys.foreign_key_columns fkc
         INNER JOIN sys.objects fk_obj
                    ON fk_obj.object_id = fkc.constraint_object_id
         INNER JOIN sys.tables fk_table
                    ON fk_table.object_id = fkc.parent_object_id
         INNER JOIN sys.schemas fk_schema
                    ON fk_table.schema_id = fk_schema.schema_id
         INNER JOIN sys.columns fk_column
                    ON fk_column.column_id = parent_column_id
                        AND fk_column.object_id = fk_table.object_id
         INNER JOIN sys.tables pk_table
                    ON pk_table.object_id = fkc.referenced_object_id
         INNER JOIN sys.schemas pk_schema
                    ON pk_table.schema_id = pk_schema.schema_id
         INNER JOIN sys.columns pk_column
                    ON pk_column.column_id = fkc.referenced_column_id
                        AND pk_column.object_id = pk_table.object_id;

SELECT
OBJECT_NAME(parent_object_id) 'Parent table',
c.NAME 'Parent column name',
OBJECT_NAME(referenced_object_id) 'Referenced table',
cref.NAME 'Referenced column name'
FROM 
sys.foreign_key_columns fkc 
INNER JOIN 
sys.columns c 
   ON fkc.parent_column_id = c.column_id 
      AND fkc.parent_object_id = c.object_id
INNER JOIN 
sys.columns cref 
   ON fkc.referenced_column_id = cref.column_id 
      AND fkc.referenced_object_id = cref.object_id  where   OBJECT_NAME(parent_object_id) = 'tablename'

如果你想获得所有表的外键关系，排除where子句，否则写你的tablename而不是tablename

确定数据库中所有表的主键和唯一键…

这应该列出所有的约束条件，在最后你可以放入过滤器

/* CAST IS DONE , SO THAT OUTPUT INTEXT FILE REMAINS WITH SCREEN LIMIT*/
WITH   ALL_KEYS_IN_TABLE (CONSTRAINT_NAME,CONSTRAINT_TYPE,PARENT_TABLE_NAME,PARENT_COL_NAME,PARENT_COL_NAME_DATA_TYPE,REFERENCE_TABLE_NAME,REFERENCE_COL_NAME) 
AS
(
SELECT  CONSTRAINT_NAME= CAST (PKnUKEY.name AS VARCHAR(30)) ,
        CONSTRAINT_TYPE=CAST (PKnUKEY.type_desc AS VARCHAR(30)) ,
        PARENT_TABLE_NAME=CAST (PKnUTable.name AS VARCHAR(30)) ,
        PARENT_COL_NAME=CAST ( PKnUKEYCol.name AS VARCHAR(30)) ,
        PARENT_COL_NAME_DATA_TYPE=  oParentColDtl.DATA_TYPE,        
        REFERENCE_TABLE_NAME='' ,
        REFERENCE_COL_NAME='' 

FROM sys.key_constraints as PKnUKEY
    INNER JOIN sys.tables as PKnUTable
            ON PKnUTable.object_id = PKnUKEY.parent_object_id
    INNER JOIN sys.index_columns as PKnUColIdx
            ON PKnUColIdx.object_id = PKnUTable.object_id
            AND PKnUColIdx.index_id = PKnUKEY.unique_index_id
    INNER JOIN sys.columns as PKnUKEYCol
            ON PKnUKEYCol.object_id = PKnUTable.object_id
            AND PKnUKEYCol.column_id = PKnUColIdx.column_id
     INNER JOIN INFORMATION_SCHEMA.COLUMNS oParentColDtl
            ON oParentColDtl.TABLE_NAME=PKnUTable.name
            AND oParentColDtl.COLUMN_NAME=PKnUKEYCol.name
UNION ALL
SELECT  CONSTRAINT_NAME= CAST (oConstraint.name AS VARCHAR(30)) ,
        CONSTRAINT_TYPE='FK',
        PARENT_TABLE_NAME=CAST (oParent.name AS VARCHAR(30)) ,
        PARENT_COL_NAME=CAST ( oParentCol.name AS VARCHAR(30)) ,
        PARENT_COL_NAME_DATA_TYPE= oParentColDtl.DATA_TYPE,     
        REFERENCE_TABLE_NAME=CAST ( oReference.name AS VARCHAR(30)) ,
        REFERENCE_COL_NAME=CAST (oReferenceCol.name AS VARCHAR(30)) 
FROM sys.foreign_key_columns FKC
    INNER JOIN sys.sysobjects oConstraint
            ON FKC.constraint_object_id=oConstraint.id 
    INNER JOIN sys.sysobjects oParent
            ON FKC.parent_object_id=oParent.id
    INNER JOIN sys.all_columns oParentCol
            ON FKC.parent_object_id=oParentCol.object_id /* ID of the object to which this column belongs.*/
            AND FKC.parent_column_id=oParentCol.column_id/* ID of the column. Is unique within the object.Column IDs might not be sequential.*/
    INNER JOIN sys.sysobjects oReference
            ON FKC.referenced_object_id=oReference.id
    INNER JOIN INFORMATION_SCHEMA.COLUMNS oParentColDtl
            ON oParentColDtl.TABLE_NAME=oParent.name
            AND oParentColDtl.COLUMN_NAME=oParentCol.name
    INNER JOIN sys.all_columns oReferenceCol
            ON FKC.referenced_object_id=oReferenceCol.object_id /* ID of the object to which this column belongs.*/
            AND FKC.referenced_column_id=oReferenceCol.column_id/* ID of the column. Is unique within the object.Column IDs might not be sequential.*/

)

select * from   ALL_KEYS_IN_TABLE
where   
    PARENT_TABLE_NAME  in ('YOUR_TABLE_NAME') 
    or REFERENCE_TABLE_NAME  in ('YOUR_TABLE_NAME')
ORDER BY PARENT_TABLE_NAME,CONSTRAINT_NAME;

如需参考，请阅读http://blogs.msdn.com/b/sqltips/archive/2005/09/16/469136.aspx