如何在 SQL Server 2008 中获取表的外键和主键详细信息

Question

我想使用 2 个查询，一个列出具有以下信息的给定表的所有外键，Schema name, foreign table name另一个列出所有主键。

这个列出主键的查询是否正确：

select syssc.name as schemaname , cast(c.name as  varchar(255)) as foreign_table , 
cast(p.name as varchar(255)) as primary_table 
from sysobjects f 
inner join sysobjects c on  f.parent_obj = c.id 
inner join sysreferences r on f.id =  r.constid 
inner join sysobjects p on r.rkeyid = p.id 
inner  join syscolumns rc on r.rkeyid = rc.id and r.rkey1 = rc.colid 
inner  join syscolumns fc on r.fkeyid = fc.id and r.fkey1 = fc.colid 
left join  syscolumns rc2 on r.rkeyid = rc2.id and r.rkey2 = rc.colid 
left join  syscolumns fc2 on r.fkeyid = fc2.id and r.fkey2 = fc.colid 
inner join sys.tables syst on rc.id=syst.object_id 
inner join sys.schemas syssc on syst.schema_id=syssc.schema_id 
where  f.type =  'F' AND c.name in ('table name' )

这是我现在用来获取外键的查询

select syssc.name as schemaname ,cast(c.name as  varchar(255)) as foreign_table ,  
cast(p.name as varchar(255)) as primary_table 
from sysobjects f 
inner join sysobjects c on  f.parent_obj = c.id 
inner join sysreferences r on f.id =  r.constid 
inner join sysobjects p on r.rkeyid = p.id 
inner  join syscolumns rc on r.rkeyid = rc.id and r.rkey1 = rc.colid 
inner  join syscolumns fc on r.fkeyid = fc.id and r.fkey1 = fc.colid 
left join  syscolumns rc2 on r.rkeyid = rc2.id and r.rkey2 = rc.colid 
left join  syscolumns fc2 on r.fkeyid = fc2.id and r.fkey2 = fc.colid 
inner join sys.tables syst on rc.id=syst.object_id 
inner join sys.schemas syssc on syst.schema_id=syssc.schema_id 
where  f.type =  'F' and p.name in ('table name')

请检查这些查询是否正确和有效。

Answer 1

您应该熟悉新的目录视图。旧的 sysobjects、syscolumns 等已被弃用，仅出于向后兼容性原因提供 - 它们不应用于新开发，旧代码最终应过渡到新对象。

这是一个查询，它将获取涉及外键的列的两侧：

SELECT 
        constraint_name   = OBJECT_NAME(fkc.constraint_object_id), 
        foreign_schema    = SCHEMA_NAME(child.[schema_id]), 
        foreign_table     = child.name, 
        foreign_column    = child_cols.name, 
        referenced_schema = SCHEMA_NAME(referenced.[schema_id]),
        referenced_table  = referenced.name, 
        referenced_column = referenced_cols.name
    FROM sys.foreign_key_columns AS fkc
    INNER JOIN sys.tables AS child
    ON fkc.parent_object_id = child.[object_id]
    INNER JOIN sys.tables AS referenced
    ON fkc.referenced_object_id = referenced.[object_id]
    INNER JOIN sys.columns AS referenced_cols
    ON fkc.parent_column_id = referenced_cols.column_id
    AND referenced_cols.[object_id] = referenced.[object_id]
    INNER JOIN sys.columns AS child_cols
    ON fkc.referenced_column_id = child_cols.column_id
    AND child_cols.[object_id] = child.[object_id]
    WHERE referenced.name = 'table name'
    -- if you want the tables that a child table references, use this instead:
    -- WHERE child.name = 'table name'
    ORDER BY fkc.parent_column_id;

而这个要简单得多，仅针对所涉及的表：

SELECT 
    constraint_name = name, 
    foreign_schema = OBJECT_SCHEMA_NAME(parent_object_id),
    foreign_table = OBJECT_NAME(parent_object_id), 
    referenced_schema = OBJECT_SCHEMA_NAME(referenced_object_id),
    referenced_table = OBJECT_NAME(referenced_object_id)
FROM sys.foreign_keys
WHERE OBJECT_NAME(referenced_object_id) = 'table name'
-- if you want the tables that a child table references, use this instead:
-- WHERE OBJECT_NAME(parent_object_id) = 'table name';

编辑添加一些指向文档的链接（这些链接主要属于 SQL Server 2008 R2 层次结构，但它们也大致等同于 SQL Server 2008）：

• 目录视图
• 查询目录视图
• 查询目录视图FAQ
• 元数据函数