Set a Comparison Date

Within AVEVA E3D Design a comparison date can be set. A convenient way of doing this is to use a stamp. However the comparison date may also be set to an explicit session on a particular extract. If the comparison session is on a different extract then the extract must be an ascendant of the current extract.

Any query may then be done at the old session using the 'OLD' keyword. for example:

Q OLD XLEN

This would return the value of XLEN at the comparison session.

Pseudo Attributes for Comparisons

There are a number of pseudo attributes that can be used to do comparisons. These are listed in the database reference manual.