Advantages

The advantages of extracts compared to simple multi-write databases are:

• Claimed elements are not released when the user changes module or exits from AVEVA base product.

• The user can save their changes to the extract, without updating the owning database until they are ready.

• The user can issue or drop partial changes.

  Extracts can be used to control approval and issuing of work. For example, changes can be issued when given criteria are met. Other users can then read the approved data rather than the working data. Using Data Access Control to control workflow is described in Data Access Control (DAC).