Článek
10/01/2010

sp_pkeys (Transact-SQL)

Returns primary key information for a single table in the current environment.

Topic link icon Transact-SQL Syntax Conventions

Syntax

sp_pkeys [ @table_name = ] 'name'     
   [ , [ @table_owner = ] 'owner' ] 
   [ , [ @table_qualifier = ] 'qualifier' ]

Arguments

[ @table_name = ] 'name'
Is the table for which to return information. name is sysname, with no default. Wildcard pattern matching is not supported.
[ @table_owner = ] 'owner'
Specifies the table owner of the specified table. owner is sysname, with a default of NULL. Wildcard pattern matching is not supported. If owner is not specified, the default table visibility rules of the underlying DBMS apply.

In SQL Server, if the current user owns a table with the specified name, the columns of that table are returned. If the owner is not specified and the current user does not own a table with the specified name, this procedure looks for a table with the specified name owned by the database owner. If one exists, the columns of that table are returned.
[ @table_qualifier = ] 'qualifier'
Is the table qualifier. qualifier is sysname, with a default of NULL. Various DBMS products support three-part naming for tables (qualifier**.owner.**name). In SQL Server, this column represents the database name. In some products, it represents the server name of the database environment of the table.

Return Code Values

None

Result Sets

Column name	Data type	Description
TABLE_QUALIFIER	sysname	Name of the table qualifier. This field can be NULL.
TABLE_OWNER	sysname	Name of the table owner. This field always returns a value.
TABLE_NAME	sysname	Name of the table. In SQL Server, this column represents the table name as listed in the sysobjects table. This field always returns a value.
COLUMN_NAME	sysname	Name of the column, for each column of the TABLE_NAME returned. In SQL Server, this column represents the column name as listed in the sys.columns table. This field always returns a value.
KEY_SEQ	smallint	Sequence number of the column in a multicolumn primary key.
PK_NAME	sysname	Primary key identifier. Returns NULL if not applicable to the data source.

Remarks

sp_pkeys returns information about columns explicitly defined with a PRIMARY KEY constraint. Because not all systems support explicitly named primary keys, the gateway implementer determines what constitutes a primary key. Note that the term primary key refers to a logical primary key for a table. It is expected that every key listed as being a logical primary key has a unique index defined on it. This unique index is also returned in sp_statistics.

The sp_pkeys stored procedure is equivalent to SQLPrimaryKeys in ODBC. The results returned are ordered by TABLE_QUALIFIER, TABLE_OWNER, TABLE_NAME, and KEY_SEQ.

Permissions

Requires SELECT permission on the schema.

Examples

The following example retrieves the primary key for the HumanResources.Department table in the AdventureWorks database.

USE AdventureWorks;
GO
EXEC sp_pkeys @table_name = N'Department'
    ,@table_owner = N'HumanResources';

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