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Comparison Tutorial

Purpose of this tutorial is to show you basic use of Data Sync.

First, we converted the standard Microsoft Northwind database from SQL Server to MySQL. We used our own state-of-the-art database converter for that.

We will explore if the conversion went well, and then tweak the data ourselves and see how Data Sync reports the differences. Here is a breakdown of what we'll do:

1. Create a new comparison project (to make sure Data Sync doesn't change the data in any way)
2. Check that databases are equal (note - we are comparing SQL Server with MySQL database here)
3. Change some data manually
4. Recompare to see that Data Sync reports the differences and shows exactly where diffs are
   

Create the new Comparison project

As we start Data Sync, you will notice a few large links for common tasks. We can either click on the Create a new project link, or click on the New button on the ribbon above.


First, we need to name our project and specify the project type. We will set the type to Comparison.

We will choose SQL Server database from the list of available source database formats and fill in connection properties. Depending on your SQL Server installation, you need to specify the server name, or server\instance name in the Server field. Note: for SQL Server Express, instance is required, like this: servername\SQLEXPRESS.

Selecting tables to convert. All by default.

You will see that six tables can't be compared at all. They are created without primary key and we need a key to be able to locate table records. This can be solved by creating a key in database, or by specifying a custom mapping in Data Sync. For this simple tutorial, we'll exclude those six tables and move on.
We will just finish the wizard and see how are our tables - healthy or corrupted?

Comparison

Data Sync is pretty fast. We use dedicated native database components instead of relying on translation libraries like ODBC which incur performance hit and often have bugs of their own. Of course, we do support ODBC to allow far wider area of supported database formats.
And, the result is... Databases are equal! So it seems both our converter and our sync tool work perfectly! Take a look at the time needed to compare. Zero seconds. Neat.

Let's make a mess. Manually.

We have now changed some things in our MySQL database, just to make sure Data Sync recognizes the differences correcty.
We deleted some records, inserted one, changed some data, changed a field from NULL to empty string.
Let's recompare! Just click the Compare button in the ribbon. And.. Of course, situation is different now.

Examining the differences

Clicking on the table name in the list opens a detailed grid with differences.
So let's examine the Categories table first. Two records are deleted and one is inserted to the MySQL database. In the details grid, you can see that records always come in two lines, in pairs. Upper line is data in reference database, and lower in work database. You can click on the button which shows the equal records as well to have a better feeling on where the differing data is related to the equal data.
By the way, the grid is much richer in the One- and Two-Way Sync modes, as you can see in the next tutorial.

That's all for this comparison tutorial. Let's continue to the One-Way Sync tutorial.

We invite you to explore Data Sync more, and, of course, to purchase it. If you want to test it yourself, just download a free trial.



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