Subject Re: [IBO] Lookup sizing issue
Author Helen Borrie
At 03:31 PM 3/05/2007, you wrote:
>In the past suing the IBO4.6 version we had some issues with the use of a
>LookupCombo and LookupList when placed within a Grid, for the purpose of
>using it as a Master-Detail relation ship.

That's the wrong interface for master-detail.

>The issue was that the first time the dropdown was access by the user, the
>autosize would not work correctly, but subsequent uses of the dropdown after
>this initial one would be perfect. By the way we never solved this.
>Now, as I am currently looking into the IBO4_7_Build16_Eval using BCB5, I
>have been asked to see if this issue (as describe above ) has been resolved.
>Unfortunately after writing a very quick demo, I find that the problem
>Could someone in the group please prove me wrong.

I don't think it's a question of proving you wrong but of your
understanding that a lookup relationship is not a master-detail
relationship and of your using the controls for the purposes they
were designed for.

-- a master detail relationship consists of one master record and 0
to n dependent records that belong to that master exclusively
(usually by way of a foreign key relationship linking the FK in the
detail record to the PK in the master)

-- a lookup relationship is the logical reverse of
master-detail. The "head" record of this relationship (in IBO it is
called the "Keysource record" contains a key that points to the PK of
a table containing unique lookup records. At any given time, any
number of head/keysource records can have an identical key value in
this field. We link the lookup record to the head record via a
Keylinks relationship. Any number of records in different tables
could point to the same underlying lookup table. It's this lack of
exclusivity, more than anything, that differentiates a master-detail
relationship from a lookup relationship.