OK – In SQL Server 2008 R2 we did “re-use” an acronym or two (DAC and DTA), but it’s important to remember there are actually two parts to this new feature. One is the Data Application Component (DAC) and the other is the Data Tier Application (DTA). The DAC is the file created for a DTA.
In SQL Server 2008R2 and Visual Studio you’ll find there is a new way to write and transfer database code. I’ll blog about it more as I finish my testing, but the process works kind of like this…
You can “birth” a Data Tier Application in two places. You can create a new project type in Visual Studio where the developer can create the database structure, put all of the policies that they want to enforce and so on there. The DBA can also right-click a database and make a Data Tier Application out of a current structure.
In both cases, something called a DAC – or Data Application Component – is created. It’s a file with the payload of the the major parts of the structure of the database and so on. that’s the “package” you use to transfer the DTA around.
From there, you right-click in the “Data Tier Application” node in SQL Server Management Studio on another Instance and “Deploy” the Data Tier Application. It will build the database for you and keep it together as a DTA. You can make changes in the “originating” system or code, and then “upgrade” the Data Tier Application.
So there you have it. It’s DTA and DAC – but I think you’ll know the difference when the time comes to use one…