Improving Availability and enhancing Programmability - Microsoft SQL Server 2008 R2 Administration - page 260

21. The Summary page lists the action steps that are to be taken to upgrade the DAC,
then click Next to continue.
22. At this point, the Upgrade DAC package process must be completed successfully.
If any errors are reported, then all the changes will be undone and rolled back by
the wizard. Once the result pane is shown as Success click Finish to complete
the wizard.
23. As a final step of confirmation, under SSMS within the Object Explorer pane, expand
the server instance, then refresh and expand the Databases node. Navigate and
browse the DAC2.0 and DAC.10 databases.
24. Finally, under the Management node, select and refresh the Data-tier Applications
node. Then, select the upgraded data-tier application and refer to the Object
Explorer Details pane to verify the new version.
This completes the list of steps to design and manage the data-tier application using the
SSMS tool.
How it works...
The design and upgrade procedures for data-tier applications are managed using the SSMS
tool. During the DACPAC deployment for new applications, the database is created along with
the required objects to store the relevant information on the DAC package. The name of the
new database contains a random string.
During the DACPAC upgrade process, the source database ( DAC1.0 ) is set to read-only mode
and all the relevant data is copied to a newly created database.
Finally, the source database is renamed, then the new database takes the name of the original
DAC1.0 database, and the DAC definition data is updated in msdb . The upgrade process is
called a side-by-side upgrade as it creates a new database to hold the newer version of DAC
objects and coexists with older DAC objects on the same instance of SQL Server.
The DAC upgrade wizard performs the following steps:
F Checks user permissions and makes sure that the application name matches
between the DAC 1.0 and the DAC 2.0 package file. System database msdb marks
the beginning of the upgrade process.
F Deployment scripts are created for the new database together with the database
objects and relevant logins. The new database for DAC 2.0 contains a random string.
F Installs the objects from the DAC 2.0 package in the new database and creates all
logins that do not already exist on the instance.
F Updates msdb to denote the deployment of DAC 2.0 and stores its definition. Sets the
database used by DAC 1.0 to read-only mode and terminates user connections to it.