SQL Server Migration – Data Migration With Different Schemas

migrationsql server

I have a database DBv1 on a SQL Server, and I want to migrate the data in it to DBv2 (on the same box, save server). DBv2 has very similar schema. The only difference in schema is that DBv2 has one less table, because it is de-normalized.

What would be the most practical way to migrate the data from DBv1 to DBv2 given that change in schema, and the need for some transformation?

Is there a tool that would do that for me? Or do I have to script that manually?

For clarification: this is a one-time load only since it is just a migration. By schema here I do not refer to the SQL object with the same name. Rather, I am referring to the structure of the tables. Due to de-normalization, one table is removed, and a new column is added to the parent table that would have the data in the deleted table.

Best Answer

You can use bcp out and bulk insert to achieve what you are trying to do.

You can use my script

Create a folder D:\BCP_OUT\ locally on the server where the bcp out files will reside.

/************************************************************************************************************************************************
Author      :   KIN SHAH    *********************************************************************************************************************
Purpose     :   Move data from one server to another or from one db to another *********************************************************************************************
DATE        :   05-28-2013  *********************************************************************************************************************
Version     :   1.0.0   *************************************************************************************************************************
RDBMS       :   MS SQL Server 2008R2 and 2012 & up  *************************************************************************************************
*************************************************************************************************************************************************/

-- save below output in a bat file by executing below in SSMS in TEXT mode. Review the OUTPUT and run the .bat file. This will create the bcp out files with data in them.
-- clean up: create a bat file with this command --> del D:\BCP_OUT\*.dat 

select '"C:\Program Files\Microsoft SQL Server\100\Tools\Binn\bcp.exe" '-- path to BCP.exe
        +  QUOTENAME(DB_NAME())+ '.'                                    -- Current Database
        +  QUOTENAME(SCHEMA_NAME(SCHEMA_ID))+'.'            
        +  QUOTENAME(name)  
        +  ' out D:\BCP_OUT\'                                           -- Path where BCP out files will be stored
        +  REPLACE(SCHEMA_NAME(schema_id),' ','') + '_' 
        +  REPLACE(name,' ','') 
        + '.dat -T -E -SSERVERNAME\INSTANCE -n'                         -- ServerName, -E will take care of Identity, -n is for Native Format
from sys.tables
where is_ms_shipped = 0 and name <> 'sysdiagrams'                       -- sysdiagrams is classified my MS as UserTable and we dont want it
and schema_name(schema_id) <> 'some_schema_exclude'                     -- Optional to exclude any schema 
order by schema_name(schema_id)                         



--- Execute this on the destination server.database from SSMS.
--- Make sure the change the @Destdbname and the bcp out path as per your environment.

declare @Destdbname sysname
set @Destdbname = 'destination_database_Name'               -- Destination Database Name where you want to Bulk Insert in
select 'BULK INSERT '                                       -- Remember Tables **must** be present on destination Database
        +  QUOTENAME(@Destdbname)+ '.'
        +  QUOTENAME(SCHEMA_NAME(SCHEMA_ID))+'.' 
        +  QUOTENAME(name) 
        + ' from ''D:\BCP_OUT\'                             -- Change here for bcp out path
        +  REPLACE(SCHEMA_NAME(schema_id),' ','') + '_'
        +  REPLACE(name,' ','') 
        +'.dat'' 
        with (
        KEEPIDENTITY,
        DATAFILETYPE = ''native'',  
        TABLOCK
        )'  + char(10) 
        + 'print ''Bulk insert for '+REPLACE(SCHEMA_NAME(schema_id),' ','') + '_'+  REPLACE(name,' ','')+' is done... '''+ char(10)+'go' 
from sys.tables
where is_ms_shipped = 0 and name <> 'sysdiagrams'           -- sysdiagrams is classified my MS as UserTable and we dont want it
and schema_name(schema_id) <> 'some_schema_exclude'         -- Optional to exclude any schema 
order by schema_name(schema_id)
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