what is ment to by a "unique index?"
It's an index which requires that every record in the table have a
different value for that field (or set of fields). That is, you can't
have any repeating values.
i get this when i
try to work on relationships. i have two tables that use
autonumbering. does this refer to the fact that both have
the same autonumbers (both have an oo1, oo2, oo3....)?
No. A unique Index applies only to one table. A relationship (in the
relationships window) links two tables (and creates a nonunique index
if you enforce referential integrity).
can you make autonumber include an alphabetical prefix
for a specific table?
No. An Autonumber has *ONE FUNCTION ONLY*: it provides an automatic,
meaningless, arbitrary unique value. Autonumbers will have gaps,
either if you delete records from the table, or even hit the <Esc> key
after you have started entering a record. You should never store two
pieces of information (e.g. a prefix and an autonumber) in the same
field in any case.
Normally in setting up relationships, you would have a "one" side
table related one-to-many to a "many" side table. The "one" side table
should have a Primary Key - a specially handled unique index - that
you use to make the relationship; the "many" side table would have a
field (referred to as a "foreign key") of the same datatype as the
primary key (a Long Integer if the primary key is an autonumber). This
should NOT be the "many" side table's primary key, and it should
certainly NOT be an Autonumber.
John W. Vinson[MVP]
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