richieasir

 Profile Answers by richieasir 

• Oct 24th, 2008

 

As you work with your application, you will want to know when Progress creates and updates indexes. Progress creates a new index entry for a record at the first occurrence of any one of the following:

 -At the end of a statement in which Progress assigns values to all components of the index entry.
 -At the end of the closest iterating subtransaction block in which the Progress 4GL creates the record.
-When Progress processes a VALIDATE statement.
-When Progress releases the record from the record buffer.
- At the end of the transaction in which Progress creates the record.

Progress updates an index at the end of any statement in which it changes the values for one or more index fields. Because Progress updates indexes immediately (at the end of an UPDATE statement), Progress immediately FINDs records in the order of the new index, while the data in the found record is unchanged. Progress changes the data in the record at the end of the scope of the record or when it releases the record.

Note: Progress does not update an index if the value you try to assign to the index field is the same as the current value of the index field. You can change the name of an index at any time.

You can also delete nonprimary indexes. However, before letting you delete a primary index, OpenEdge requires that you first designate another index as primary.

If there is only one index, you must create a new index before deleting the existing index. You cannot change any of the component definitions of an index. Instead, you must delete the index and re-create it using the modified component definitions.

Remember that OpenEdge assumes that the first index you create is the primary index, so create your primary index first. Using the 4GL

richieasir

 Profile Answers by richieasir 

• Oct 24th, 2008

 

database  engines are one of the strength for progress.it has two db engines-sql92 and 4gl.4GL concepts is also a great strength for progress database.

 sql92 and 4gl engines are different but both can be used against a single database. even installing sql92 engine doesn't reduce the performance of 4gl engines.u can say bith engines as a security models for the database.

these engines wil take care during crash of database,recovery prosess from storage devices(ai,bi,tl).sql clients can connect thro sql92 engine and 4gl clients can connect thro 4gl engine.