DAC is the short name for the Data Warehouse Administration Console.
DAC consists of the DAC client, which is written in a Java program, and a DAC database repository.
DAC client connects to the repository database using JDBC. You need to install JDBC drivers in order to connect to the DAC database. A DAC client can access multiple DAC database repositories. If your DAC repositories are stored in different type of databases. You just need to have the different JDBC drivers installed in your DAC Lib file director.
The DAC client’s version needs to be the same as the DAC repository it connects to. Otherwise, you will not be able to access the repository.
- If you use an old version of DAC client to connect to a new version of DAC repository, you will get a message, said “The repository you are connecting to is of an incompatible version. The system will shut down”. This means that if you have multiple repositories installed in different versions. You will need to install different version of DAC.
- If you use a newer version of DAC client to connect to a older version DAC repository, it will ask if you want to upgrade the repository. Once you upgrade the repository, you will not be able to access it using the older version of DAC client.
Many client/server applications, or specifically thick client applications, exists the IT support problem of keeping the client and server in the same version. DAC’s architecture by nature has the problem, but DAC is only for adminstrators, not really for end users. In a multi-user environments, or multi-admin environment, you will need to ensure that all the users are using the latest DAC client before you upgrade the server. Or the DAC client software needs to be available in a shared directory so the administrators can upgrade their clients when they received the above messages.