sp_describe_cursor_tables (Transact-SQL)

Artykuł
02/13/2015

Reports the objects or base tables referenced by a server cursor.

Ikona łącza do tematu Transact-SQL Syntax Conventions

Składnia

sp_describe_cursor_tables 
     [ @cursor_return = ] output_cursor_variable OUTPUT 
     { [ , [ @cursor_source = ] N'local'
     , [ @cursor_identity = ] N'local_cursor_name' ] 
   | [ , [ @cursor_source = ] N'global'
     , [ @cursor_identity = ] N'global_cursor_name' ] 
   | [ , [ @cursor_source = ] N'variable'
     , [ @cursor_identity = ] N'input_cursor_variable' ] 
     } 
[;]

Arguments

[ @cursor\_return= ] output_cursor_variableOUTPUT
Is the name of a declared cursor variable to receive the cursor output. output_cursor_variable is cursor, with no default, and must not be associated with any cursors at the time sp_describe_cursor_tables is called. The cursor returned is a scrollable, dynamic, read-only cursor.
[ @cursor\_source= ] { N'local' | N'global' | N'variable' }
Specifies whether the cursor being reported on is specified by using the name of a local cursor, a global cursor, or a cursor variable. The parameter is nvarchar(30).
[ @cursor\_identity= ] N'local_cursor_name'
Is the name of a cursor created by a DECLARE CURSOR statement either having the LOCAL keyword, or that defaulted to LOCAL. local_cursor_name is nvarchar(128).
[ @cursor\_identity= ] N'global_cursor_name'
Is the name of a cursor created by a DECLARE CURSOR statement either having the GLOBAL keyword, or that defaulted to GLOBAL. global_cursor_name can also be the name of an API server cursor opened by an ODBC application that then named the cursor by calling SQLSetCursorName.global_cursor_name is nvarchar(128).
[ @cursor\_identity= ] N'input_cursor_variable'
Is the name of a cursor variable associated with an open cursor. input_cursor_variable is nvarchar(128).

Return Code Values

None

Cursors Returned

sp_describe_cursor_tables encapsulates its report as a Transact-SQL cursor output parameter. This enables Transact-SQL batches, stored procedures, and triggers to work with the output one row at a time. This also means that the procedure cannot be called directly from API functions. The cursor output parameter must be bound to a program variable, but the APIs do not support bind cursor parameters or variables.

The following table shows the format of the cursor that is returned by sp_describe_cursor_tables.

Column name	Data type	Description
table owner	sysname	User ID of the table owner.
Table_name	sysname	Name of the object or base table. In SQL Server, server cursors always return the user-specified object, not the base tables.
Optimizer_hints	smallint	Bitmap that is made up of one or more of the following: 1 = Row-level locking (ROWLOCK) 4 = Page-level locking (PAGELOCK) 8 = Table lock (TABLOCK) 16 = Exclusive table lock (TABLOCKX) 32 = Update lock (UPDLOCK) 64 = No lock (NOLOCK) 128 = Fast first-row option (FASTFIRST) 4096 = Read repeatable semantic when used with DECLARE CURSOR (HOLDLOCK) When multiple options are supplied, the system uses the most restrictive. However, sp_describe_cursor_tables shows the flags that are specified in the query.
lock_type	smallint	Scroll-lock type requested either explicitly or implicitly for each base table that underlies this cursor. The value can be one of the following: 0 = None 1 = Shared 3 = Update
server_name	sysname, nullable	Name of the linked server that the table resides on. NULL when OPENQUERY or OPENROWSET are used.
Objectid	int	Object ID of the table. 0 when OPENQUERY or OPENROWSET are used.
dbid	int	ID of the database that the table resides in. 0 when OPENQUERY or OPENROWSET are used.
dbname	sysname, nullable	Name of the database that the table resides in. NULL when OPENQUERY or OPENROWSET are used.

Uwagi

sp_describe_cursor_tables describes the base tables that are referenced by a server cursor. For a description of the attributes of the result set returned by the cursor, use sp_describe_cursor_columns. For a description of the global characteristics of the cursor, such as its scrollability and updatability, use sp_describe_cursor. To obtain a report of the Transact-SQL server cursors that are visible on the connection, use sp_cursor_list.

Permissions

Requires membership in the public role.

Examples

The following example opens a global cursor and uses sp_describe_cursor_tables to report on the tables that are referenced by the cursor.

USE AdventureWorks2012;
GO
-- Declare and open a global cursor.
DECLARE abc CURSOR KEYSET FOR
SELECT LastName
FROM Person.Person
WHERE LastName LIKE 'S%';

OPEN abc;
GO
-- Declare a cursor variable to hold the cursor output variable
-- from sp_describe_cursor_tables.
DECLARE @Report CURSOR;

-- Execute sp_describe_cursor_tables into the cursor variable.
EXEC master.dbo.sp_describe_cursor_tables
      @cursor_return = @Report OUTPUT,
      @cursor_source = N'global', @cursor_identity = N'abc';

-- Fetch all the rows from the sp_describe_cursor_tables output cursor.
FETCH NEXT from @Report;
WHILE (@@FETCH_STATUS <> -1)
BEGIN
   FETCH NEXT from @Report;
END

-- Close and deallocate the cursor from sp_describe_cursor_tables.
CLOSE @Report;
DEALLOCATE @Report;
GO

-- Close and deallocate the original cursor.
CLOSE abc;
DEALLOCATE abc;
GO