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Give up the DDS. You can use DDL to generate indexes and views against a
table, even if the original table was created with DDS.

Speaking of indexes and views they are, generally speaking, two different
objects.
The main purpose of an index is to speed access to the data.
The main purpose of a view is for data selection and presentation.
Using a view may be improved by also having an index. For example, if you
have a view that selects by date of a column it will perform better if you
also have an index over that column.

You don't "need" either an index or a view if you decide to build all your
selection criteria and whatnot into your SELECT statement. But the combo
can simplify your selection and improve the performance.

Speaking of performing better, it really helps to tailor your selection
based on this index. For example, if you store your dates as decimal 8,0
where the number is represented by CCYYMMDD then it's better to have
where ohordt=datetonum(current date)
than
where numtodate(ohordt)=current date
Either will work but the former will use your index. You are not allowed
to create an index over numtodate(ohordt).


Rob Berendt

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