I work for a little insurance company in France.
My company is actually installing db2 on zos (mainframe) and cobol. As we don't have no DBA, i would have some answers about a question:
- What would be the advantages or disadvantages about
1/ Writting an unique access module for each table (this module would have lots of fonctions)
For example if the Table has three rows, when i do my select, it would have 6 fonctions because there are 6 possibilities about the where clause and may be 12 possibilities if we add the order by / group by clause
2/ Coding all sql order in the program
If theres is a DBA or poeple who knows DB very well here, any advice would be great.
In our company we have used since 1992 the first option (before that, we used option 2). But now it seems to be, that it was a misstake, because if you use access modules...
a) you can't use SQL JOINS - leading to performance problems
b) you will read too many columns. Each and every column adds your CPU-cost.
c) SQL is an interface to the database. Why should you build an interface over an interface?