Subject Re: [IBO] TIBOQuery - editing contents from grid
Author Helen Borrie
At 10:34 PM 6/05/2004 +0000, you wrote:
>Thanks Helen!!!
>
>I will look into KeyRelation and the KeyLinks settings - that sounds
>like what I need!
>
>Both Access and MS SQL (7+) appear to allow editable/live joined
>datasets... with a few caveats of course<grin>.
>
>As for the SQL syntax... well back in the 80's that SQL was pretty as
>a picture... I am slowly forcing myself to use the new(er) syntax...
>it is just taking a few years. :)
>
>When you have lets say 4 joined tables... is is better/worse to use
>parens in the FROM clause and how do you "know" to join one set of
>tables "first" and then add the next one or maybe the other one??? Is
>there a correct order to place the JOINS or will the optimizer ignore
>me (which it probably should) and join the tables the way it thinks
>is best.... and is that still the case if I use parens (correctly or
>incorrectly)???

It's a big question - designing joined queries. The most important choice
is the one at the left side, because it largely drives what will be the
"keys" of the output. Apart from the leftmost table, the order of the
other tables doesn't matter: joins are based on matching the keys and the
actual rows that are "in" or "out" depends on the where clause.

About parens in the FROM clause, I'm not clear what you are talking
about. Could you give an example?

>Thanks a ton! - I sure need your book about now! :)

Don't we all?!?!?

Helen