Multiple Databases

To control what data a user can see, databases are grouped into Multiple Databases (MDBs). A project will contain at least one MDB. A database may be a member of any number of MDBs.

An MDB must contain all the data that the user needs to access. For example, for a Model user, the MDB must contain a Catalogue database and the Model database on which the user is going to work. In addition, the MDB should contain all other Model databases with data in the same physical volume, which will make sure the accuracy of clash checking, and all other Model databases which will have connections to the user’s design area.

Many users can access the same MDB. There are different ways of allowing access to MDBs: some options are described below:

1. One MDB per User. The Database (DB) with write access must be the first DB of that type (Model, Draft, etc.) in the MDB’s list of members. This option may be suitable for large projects with many DBs and Users.

2. One MDB with many users. In this case, the System Administrator can create the first-level elements in the DB, for example, Sites or Departments, which avoids having to use the Defer and Current options to move the required database to the top of the list (refer to Database Sets). This option is often suitable for small to medium projects with few DBs and Users, or where multi-write DBs are being used.

3. MDBs for special purposes. For example, an MDB containing Piping data only for MTO production, etc.

The order of databases in an MDB is important. In a new project, if there is more than one database of the type the user is going to write to, the AVEVA base product will try to write to the first one in the MDB list. This means that when the user starts to create top-level elements (Sites, Departments, etc.) they will be created in the first database in the MDB. This means that the user must have write access to the first database in the list.