在存儲過程裏實現分頁的邏輯,爽是爽,但造成與數據庫耦合和壓力,這是它最明顯的缺點,但是,在某些情況,存儲過程分頁,依然是最有效的選擇。
一下是sql server中實現的代碼。
- File: dbo.SingleTablePager
-- Date: 2007-09-29 AM 11:09
-- Desc: 單表分頁函數
if exists(select * from sysobjects where name = N'SingleTablePager' and type = 'FN')
DROP FUNCTION dbo.SingleTablePager
GO
CREATE FUNCTION dbo.SingleTablePager
(
@Key VARCHAR(32), --用於分頁的key
@DbTableName VARCHAR(32), --讀取數據的數據表
@FldNames VARCHAR(256), --讀取的字段列表
@WhrPattern VARCHAR(512), --where後面的條件列表 (包括where)
@Sort VARCHAR(4), --排序方法,只能是desc和asc
@SortPattern VARCHAR(64), --排序的sql代碼片斷(包括order by)
@PageIndex INT, --當前頁碼
@PageSize INT --每頁多少條數據
) RETURNS VARCHAR(1024)
AS
BEGIN
DECLARE @Sql VARCHAR(1024)
SET @Sql = 'SELECT TOP ' + CAST(@PageSize AS VARCHAR) + ' ' + @FldNames + ' FROM ' + @DbTableName + ' '
IF @PageIndex = 1
SET @Sql = @Sql + @WhrPattern
ELSE
BEGIN
IF LOWER(@Sort) = 'desc'
BEGIN
IF @WhrPattern <> ''
SET @Sql = @Sql + @WhrPattern + 'AND ' + @Key + ' < ('
ELSE
SET @Sql = @Sql + 'WHERE ' + @Key + ' < ('
SET @Sql = @Sql + 'SELECT MIN(' + @Key + ') FROM (SELECT TOP ' + CAST((@PageIndex - 1) * @PageSize AS VARCHAR) + ' ' + @Key + ' FROM ' + @DbTableName + ' ' + @WhrPattern + ' ' + @SortPattern + ') AS TempTable) '
END
ELSE
BEGIN
IF @WhrPattern <> ''
SET @Sql = @Sql + @WhrPattern + 'AND ' + @Key + ' > ('
ELSE
SET @Sql = @Sql + 'WHERE ' + @Key + ' > ('
SET @Sql = @Sql + 'SELECT MAX(' + @Key + ') FROM (SELECT TOP ' + CAST((@PageIndex - 1) * @PageSize AS VARCHAR) + ' ' + @Key + ' FROM ' + @DbTableName + ' ' + @WhrPattern + ' ' + @SortPattern + ') AS TempTable) '
END
END
SET @Sql = @Sql + @SortPattern
RETURN @Sql
END
GO
運用實例:
- File: dbo.Woruhe_QeuryAllNoApprovedPrimaryPhotos
-- Date: 2007-12-12 3:18 PM
-- Desc: 分頁顯示所有等待中的主照片
if exists(select * from sysobjects where name = ('Woruhe_QeuryAllNoApprovedPrimaryPhotos') and type = 'P')
DROP PROCEDURE dbo.Woruhe_QeuryAllNoApprovedPrimaryPhotos
GO
CREATE PROCEDURE dbo.Woruhe_QeuryAllNoApprovedPrimaryPhotos
(
@PageIndex INT,
@PageSize INT
)
AS
BEGIN
DECLARE @Sql NVARCHAR(1024)
DECLARE @WhereSql VARCHAR(512)
SET @WhereSql = 'WHERE IsPubliclyRated = 0 and IsPrimary = 1'
SET @Sql = dbo.SingleTablePager('PhotoID', 'PhotoApproveQueue', '*', @WhereSql, 'DESC', 'ORDER BY PhotoID DESC', @PageIndex, @PageSize)
--EXEC(@Sql)
EXEC (@Sql)
SET @Sql = 'SELECT COUNT(1) FROM PhotoApproveQueue ' + @WhereSql
Exec (@Sql)
END
GO