The following table compares the features of the OpenEdge and Oracle sequence generators. An application that relies on sequence generators can access an OpenEdge database and, through the DataServer, an Oracle database. See the chapter on database access in Develop ABL Applications for information on defining and using OpenEdge sequences in your database applications.

Table 1. OpenEdge and Oracle sequence generators
Characteristic OpenEdge Oracle
Maximum/minimum range Yes Yes
Ascending/descending Yes Yes
Adjustable incrementation Yes Yes
Database object Yes Yes
Loses a number when a record creation fails Yes Yes
Sequence is disrupted during dumping or loading No Yes

If you add a sequence to a table in your supporting Oracle database, you must update the schema image to reflect this addition. See The DataServer Tutorial for instructions on updating a schema image.

There are two ABL functions that provide information about database sequences, NEXT-VALUE and CURRENT-VALUE. When you use the DataServer, you can use these functions to get information about sequences in your Oracle database, but you must use the NEXT-VALUE function first in the same session you use the CURRENT-VALUE function.