SQL Server 2008：找出表中的主键/外键？

Question

有没有人知道我怎么能看到哪一个表中的主键&外键？

编辑：感谢所有的答复。我正在寻找一个SQL查询来做到这一点。现在我正在写一个工具，它可以列出所有DB的表格并显示列。我想显示哪些键是主键。

这是我读出表目录：

const string sqlSelectTable = "SELECT TABLE_CATALOG, TABLE_SCHEMA, TABLE_NAME, TABLE_TYPE " + 
             "FROM INFORMATION_SCHEMA.TABLES " + 
             "WHERE TABLE_TYPE = 'BASE TABLE' " + 
             "ORDER BY TABLE_TYPE,TABLE_NAME"; 

而且这是我得到的相关信息约一列：

const string sqlSelectTable = 
      "SELECT  COLUMN_NAME, DATA_TYPE, CHARACTER_MAXIMUM_LENGTH " + 
      "FROM   INFORMATION_SCHEMA.COLUMNS " + 
      "WHERE  (TABLE_NAME = @TABLE_NAME) " + 
      "ORDER BY ORDINAL_POSITION"; 

我必须创建一个内加入这样看哪列是主键？

干杯

Answer 1

有关各表的主键，您可以使用此查询：

SELECT 
    kc.name, 
    c.NAME 
FROM 
    sys.key_constraints kc 
INNER JOIN 
    sys.index_columns ic ON kc.parent_object_id = ic.object_id 
INNER JOIN 
    sys.columns c ON ic.object_id = c.object_id AND ic.column_id = c.column_id 
WHERE 
    kc.type = 'PK' 

和对于外键，我相信这个查询应该会为你提供必要的信息：

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 

马克

Answer 2

在Management Studio中，展开表格，然后展开“列”项目。主键旁边有一个钥匙图标。

要查看外键，请展开Constraints项目。

Answer 3

看到Querying the SQL Server System Catalog FAQ，How do I find the columns of a primary key for a specified table?和How do I find the columns of a foreign key for a specified table?

编辑：如果你想这样做编程方式（这是不是从你的问题清楚），那是。

Answer 4

你可以开始：

SELECT 
    Table_Name as [TableName], 
    Column_Name as [ColumnName], 
    Constraint_Name as [Constraint], 
    Table_Schema as [Schema] 
FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE 
ORDER BY 
    [TableName], 
    [ColumnName] 

（您可以通过表名过滤然后）

Answer 5

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' 

如果你想获得的所有表的外键关系，排除其他的where条款写你的表名，而不是tablename