Kbase P36102: Calculated fields => Use Joins instead when possible
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
08/08/2003 |
|
Status: Unverified
SYMPTOM(s):
SDO has a calculated field
Any problem
CAUSE:
SDO has a calculated field although a join could be used instead
FIX:
Many developers use a calculated field to retrieve data from another table.
Many time, such a calculated field could be avoided by relying on a Joined table instead. This also results in better performance.
Indeed, when relying on a calculated field, procedure DATA.CALCULATE is fired each time a record is added in RowObject temp-table (in adm2/query.p/transferDBRow). This is just slower than a QUERY with joins, which is handled at the 4GL core level.
In other word, the query should look like:
FOR EACH TableA NO-LOCK, FIRST TableB [OUTER-JOIN] [OF TableA | WHERE expression] NO-LOCK