Re: [INTERFACES] calculated identity field in views, again...

--- Zlatko Matic <zlatko(dot)matic1(at)sb(dot)t-com(dot)hr> wrote:
> I asked this question several weeks ago, but nobody
> proposed a solution, so
> I am repeating the same question again...
> I have an MS Access front-end for a database on
> PostgreSQL.
> I could use pass-through queries as record sources
> for reports and it works
> fine...
> Unfortunately, MS Access doesn't allow pass-through
> queries to be records
> sources for subforms.

Unless you use unbound form/controls. Which means
handling everything in code, which might work out best
for you, depending on what you want (this is
effectively equivalent to the VB-only option which
someone else mentioned).

> Therefore I tried to base subforms on regular JET
> queries on linked tables.
> It was too slow...
> Then I tried to base subforms on DAO recordset code
> generated from
> pass-through QueryDef objects. Although it worked,
> it was very unstable...
>
> Now it seems to me that POstgreSQL views are the
> best solution, but Access
> considers views as tables (!) and needs column with
> unique values.

AFAIK a composite key (combination of several columns)
should work ok for a primary key for Access. When
linking to the view, just select the columns you want
to use. Or are you saying that you tried this, and it
didn't work?

Alternatively, you could try including in your view
definition the oid column for each of the constituent
tables. If I understand right, oids are globally
unique within your database. This assumes that you
have created your tables with oids, which may not be
the case.

Basing a subform on a mult-table join sounds like odd
database design. Perhaps if you can explain more
about what you are trying to do, people can offer more
suggestions.

> All those views are complicated queries on several
> tables, so I can't use
> any table's column as primary key. I need a
> calculated column in the view
> that Access will consider as primary key column.
> In regular tables, I use bigserial field, but how
> can I create calculated
> bigserial column in a view ?
>
> Thanks.
>
>
> ---------------------------(end of
> broadcast)---------------------------
> TIP 9: the planner will ignore your desire to choose
> an index scan if your
> joining column's datatypes do not match
>

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