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  • 数据库的常用命令

    1)在数据库中建立新列

    ALTER TABLE dbo.DataDictionary ADD IsDefaultSelect  BIT     

    1:IsDefaultSelect 加的字段名称

    2:BIT 该字段的类型

    数据类型有:

    2)更改字段名字

    EXEC sp_rename 'dbo.DataDictionary.[GroupNO]', 'GroupNo', 'column' 

    3)数据库建表

    CREATE TABLE LimitSetting

    (

     [Id] [int] IDENTITY(1,1) NOT NULL,

     [UpdateDate] [datetime] NULL,

     [Remark] [varchar](100) NULL,

     [IsValid] [bit] NULL,

     [AddDate] [datetime] NULL,

     )

    4)开启时间和IO

    set statistics io on
    set statistics time on;

    5)查看索引碎片

    Declare @db SysName;
    Set @db = 'dbo.DataDictionary';
     
    SELECT CAST(OBJECT_NAME(S.Object_ID, DB_ID(@db)) AS VARCHAR(20)) AS 'tableName',
     CAST(index_type_desc AS VARCHAR(20)) AS 'Index Type',
     I.Name As 'Index Name',
     avg_fragmentation_in_percent As 'Avg % Fragmentation',
     record_count As 'RecordCount',
     page_count As 'Pages Allocated',
     avg_page_space_used_in_percent As 'Avg % Page Space Used'
    FROM sys.dm_db_index_physical_stats (DB_ID(@db),NULL,NULL,NULL,'DETAILED' ) S
    LEFT OUTER JOIN sys.indexes I On (I.Object_ID = S.Object_ID and I.Index_ID = S.Index_ID)
    AND S.INDEX_ID > 0
    ORDER BY avg_fragmentation_in_percent DESC
     

    6)关于索引

     下面语句可以重建指定表的所有索引:

    ALTER INDEX ALL ON <Table Name> REBUILD;

        下面语句可以重建指定索引:

    ALTER INDEX <Index Name> ON <Table Name> REBUILD;

        当然,我们也可以整理索引,下面语句整理指定表上的所有索引:

    ALTER INDEX ALL ON <Table Name> REORGANIZE;

        下面语句指定特定的索引进行整理:

    ALTER INDEX <Index Name> ON <Table Name> REORGANIZE;

    在重建或整理完索引之后,重新运行上面的语句来查看索引碎片的情况。

    有时候不是我们失去了目标,而是失去了方向。
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  • 原文地址:https://www.cnblogs.com/871735097-/p/3760897.html
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