clearing all the data in the database

  • This may seem like a rookie question, but I need to clear a backend database of all sample data and defaults for a clean install, and haven't fingured out how to do all the tables at once? I'm having to clear each table one at a time.

  • Write a script to pull the table names out of sysobjects where xtype = 'U'. Something to the effect of :

    Select 'Truncate Table ' + name

    From sysobjects

    Where xtype = 'U'

    Take the result set and then execute it in another window. Also, there are a number of scripts to do this kind of admin stuff in the scripts section of this web site.

    Remember this when a developer tells you it will just be temporary. Temporary = Permanent.

  • Also do not forget to update statistics after truncating the tables.

    .

  • Don't mean to be picky but have you thought of using the INFORMATION_SCHEMA.TABLES view to get the tables listing? This is based upon the sysobjects table but is the preferred method of accessing the system tables. It's supposed to put a layer of transparency between the programmer and the system tables.

    Sean

  • We can use this sp to clear data in tables.

    This sp will clear the foriegn key table first and followed by primary key table.

    I have used Delete and Truncate statement to clear the data. Please refer SQL Books online difference of Delete and Truncate statement.

    if exists (select * from sysobjects where id = object_id(N'[dbo].[ClearTableData]') and OBJECTPROPERTY(id, N'IsProcedure') = 1)

    drop procedure [dbo].[ClearTableData]

    GO

    Create Proc ClearTableData

    As

    Declare @TableName Varchar(1000), @Reference Varchar(4), @sql Varchar(8000), @ObjectName Varchar(8000),

    @TabName Varchar(1000)

    SET NOCOUNT ON

    If db_name() In ('master', 'model', 'msdb', 'tempdb')

    Begin

    Print 'system database are not allowed to clear'

    return 0

    End

    Set @ObjectName = ''

    Set @TabName = ''

    -- Delete data in Child Object and its Parent Object

    Begin

    DECLARE ClearTableData_Cursor CURSOR FOR

    Select SO.Name "ChildObject",

    Case When (Select Count(*) From SysReferences Where rkeyid = SO.id) = 0 Then 'N' Else 'Y' End As Ref

    From SysObjects SO, SysReferences SR, SysObjects SO1

    Where SO.id = SR.fkeyid And SO.xtype = 'U' And SO1.ID = SR.rkeyid

    Order By SO1.Name Desc, SO.Name

    OPEN ClearTableData_Cursor

    FETCH NEXT FROM ClearTableData_Cursor

    INTO @TableName, @Reference

    WHILE @@FETCH_STATUS = 0

    BEGIN

    If @Reference = 'Y'

    Begin

    -- Concatenate Primary Key Table name

    Set @ObjectName = @ObjectName + ',' + @TableName

    End

    Else If @Reference = 'N'

    Begin

    Begin

    -- Clear data from Foreign Key Tables(Child object)

    Set @sql = ''

    Set @sql = 'Truncate Table [' + @TableName + ']'

    exec (@SQL)

    End

    End

    FETCH NEXT FROM ClearTableData_Cursor

    INTO @TableName, @Reference

    END

    CLOSE ClearTableData_Cursor

    DEALLOCATE ClearTableData_Cursor

    If Len(@Reference) > 0

    Begin

    -- Clear data for Concatenated Primary Key Tables

    Set @ObjectName = Right(@ObjectName,Len(@ObjectName)-1)

    While Len(@ObjectName) > 0

    Begin

    If (CHARINDEX(',',@ObjectName) > 0)

    Begin

    Set @TabName = Substring(@ObjectName, 1, CharIndex(',',@ObjectName)-1)

    Set @ObjectName = SUBSTRING(@ObjectName, Len(@TabName) + 2, Len(@ObjectName))

    End

    Else

    Begin

    Set @TabName = @ObjectName

    Set @ObjectName = ''

    End

    Begin

    Set @sql = ''

    Set @sql = 'DELETE From [' + @TabName + ']'

    exec (@SQL)

    End

    End

    End

    End

    --Delete Data in Standalone Parent Object

    Begin

    DECLARE ClearTableData_Cursor CURSOR FOR

    Select Distinct SO.Name "ChildObject"

    From SysObjects SO

    Where (SO.id In (Select rkeyid From SysReferences))

    And SO.xtype = 'U'

    Order By SO.Name

    OPEN ClearTableData_Cursor

    FETCH NEXT FROM ClearTableData_Cursor

    INTO @TableName

    WHILE @@FETCH_STATUS = 0

    BEGIN

    Begin

    Set @sql = ''

    Set @sql = 'DELETE From [' + @TableName + ']'

    exec (@SQL)

    End

    FETCH NEXT FROM ClearTableData_Cursor

    INTO @TableName

    END

    CLOSE ClearTableData_Cursor

    DEALLOCATE ClearTableData_Cursor

    End

    -- Delete data for BaseDate/Master Table

    Begin

    DECLARE ClearTableData_Cursor CURSOR FOR

    Select Distinct SO.Name "ChildObject"

    From SysObjects SO

    Where (SO.id Not In (Select rkeyid From SysReferences) And SO.id Not In (Select fkeyid From SysReferences))

    And SO.xtype = 'U'

    Order By SO.Name

    OPEN ClearTableData_Cursor

    FETCH NEXT FROM ClearTableData_Cursor

    INTO @TableName

    WHILE @@FETCH_STATUS = 0

    BEGIN

    Begin

    Set @sql = ''

    Set @sql = 'Truncate Table [' + @TableName + ']'

    exec (@SQL)

    End

    FETCH NEXT FROM ClearTableData_Cursor

    INTO @TableName

    END

    CLOSE ClearTableData_Cursor

    DEALLOCATE ClearTableData_Cursor

    End

    SET NOCOUNT OFF

    [/code ends here]

    Blog: Gulappa

  • You need just one line of code to clear all your user tbles.

    exec sp_MSforeachtable 'truncate table ?'

  • What a top bit of code. I'm all for the simple option (sp_msforeachtable).

    Sean

  • Actually when you look at the code of this procedure you will know why it is undocumented, but I agree that you won't get a 'shorter' solution to type.

    Frank

    http://www.insidesql.de

    http://www.familienzirkus.de

    --
    Frank Kalis
    Microsoft SQL Server MVP
    Webmaster: http://www.insidesql.org/blogs
    My blog: http://www.insidesql.org/blogs/frankkalis/[/url]

  • Or you just generate the creation script of your database.

    Then drop the DB and recreate it by applying the creation script.

    This is the cleanest (and also the fastest) way to have a startup, ready to deploy database

    Bye

    Gabor



    Bye
    Gabor

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