How can I copy and overwrite data of tables from database1 to database2 in SQL Server

Question

I have a database1 which has more than 500 tables and I have database2 which also has the same number of tables and in both the databases the name of tables are same.. some of the tables have different table definitions, for example a table reports in database1 has 9 columns and the table reports in database2 has 10.

I want to copy all the data from database1 to database2 and it should overwrite the same data and append the columns if structure does not match. I have tried the import export wizard in SQL Server 2008 but it gives an error when it comes to the last step of copying rows. I don't have the screen shot of that error right now, it is my office PC. It says that error inserting into the readonly column xyz , some times it says that vs_isbroken , for the read only column error as I mentioned a enabled the identity insert but it did not help..

Please help me. It is an opportunity in my office for me.

Answer 1

SSIS and SQL Server 2008 Wizards can be finicky tools.

If you get a "can't insert into column ABC", then it could be one of the following:

• Inserting into a PK column -> when setting up the mappings, you need to indicate to overwrite the value
• Inserting into a column with a smaller range -> for example from nvarchar(256) into nvarchar(50)
• Inserting into a calculated column (pointed out by @Nick.McDermaid)

You could also get issues with referential integrity if your database uses this (most do).

If you're going to do this more often, then I suggest you build an SSIS package instead of using the wizard tooling. This way you will see warnings on all sorts of issues like the ones I've described above. You can then run your package on demand.

Another suggestion I would make, is that you insert DB1 into "stage" tables in DB2. These tables should have no relational integrity and will allow you to break the process into several steps as follows.

• Stage the data from DB1 into DB2
• Produce reports/queries on issues pertinent to your database/rules
• Merge the data from stage tables into target tables using SQL

That last step is where you can use merge statements, or simple insert/updates depending on a key match. Using SQL here in the local database is then able to use set theory to manage the overlap of the two sets and figure out what is new or to be updated.

SSIS "can" do this, but you will not be able to do a bulk update using SSIS, whereas with SQL you can. SSIS would do what is known as RBAR (row by agonizing row), something slow and to be avoided.

I suggest you inform your seniors that this will take a little longer to ensure it is reliable and the results reportable. Then work step by step, reporting on each stages completion.

Another two small suggestions:

• Create _Archive tables of each of the stage tables and add a Tstamp column to each. Merge into these after the stage step which will allow you to quickly see when which rows were introduced into DB2
• After stage and before the SQL merge step, create indexes on your stage tables. This will improve the merge performance
• Drop those Indexes after each merge, this will increase the bulk insert Performance

Basic on Staging (response to question clarification):

Links:

• http://www.codeproject.com/Articles/173918/How-to-Create-your-First-SQL-Server-Integration-Se
• http://www.jasonstrate.com/tag/31daysssis/
• http://blogs.msdn.com/b/andreasderuiter/archive/2012/12/05/designing-an-etl-process-with-ssis-two-approaches-to-extracting-and-transforming-data.aspx

Staging is the act of moving data from one place to another without any checks.

1. First you need to create the target tables, the schema should match the source tables.
2. Open up BIDS and create a new Project and in it a new SSIS package.
3. In the package, create a connection for the source server and another for the destination.
4. Then create a data flow step, in the step create a data source for each table you want to copy from.
5. Connect each source to a new data destination and set the appropriate connection and table.
6. When done, save and do a test run.

Before the data flow step, you might like to add a SQL step that will truncate all the target tables.

Answer 2

If you're open to using tools then what about using something like Red Gate Sql Compare and Red Gate SQL Data Compare ?

First I would use data compare to manage the schema differences, add the new columns you want to your destination database (database2) from the source (database1). Then with data compare you match the contents of the tables any columns it can't match based on names you specify how to handle. Then you can pick and choose what data you want to copy from your destination. So you'll see what data is new and what's different (you can delete data in the destination that's not in the source or ignore it). You can either have the tool do the work or create you a script to run when you want.

There's a 15 day trial if you want to experiment.

Answer 3

似乎您正在寻找SQL Server Replication提供的Replication技术。

Answer 4

Well, if i understood your requirement correctly, you need to make database2 a replica of database1. Why not take a full backup of database1 and restore it as database2? Your database2 will be exactly what database1 is at the time of backup.