Klatuu said:
It is a good idea to create an index for any field that may be used for
querying or looking up data. It makes it much faster. You create indexes in
Table Design view. You have probably seen it ask you if you wanted to create
a Primary Key. That is the main index of the table, and should be set on the
field or fields that will most often be used to retrieve data from the table.
Many people have been mystified by the really s - l - o - w performance
of their databases, not noticing that they should have defined some
indices. But don't overdo it -- too many indices will make Access do
extra work when you try to update your Tables. Add them only to the
fields that need them.
Besides improving performance (speeding up references), you can also
make an index check that you have no duplicate values. For example, if
you have a Table in which one field identifies a student and another
field identifies a class that the student is taking, then you could
define an index on those 2 fields that prevents your entering a new
record in which both the student and the class duplicate those same
fields in some previous record. (E.g., you want only one record showing
that "Debbie" is enrolled in "Abstract Hydrodynamics" -- trying to add
another one will raise an error message if you've defined the proper
index on those 2 fields.)
-- Vincent Johns <
[email protected]>
Please feel free to quote anything I say here.
