Setting Query 'Current Row' with Result Data From 2nd 'Search' Query
lazarus / 16-Databases

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mrmikehicks · 2009-08-31 16:09

I have Lazarus and Firebird working great on both MAC (OS X) and PC
(Vista Home Virus.)
I have a fb database with number of tables. This is only about one
table. All the zeoslib
components are setup and working correctly. I start with some dbmemo
and dbedit fields
on the form and fill them with the main query (select * from table.) A
dbnavigator clicks thru
the query and all is working fine. I also have on the form, a search
button, that calls a lookup
dbgrid form that takes in the search argument and uses a 2nd 'search'
query to select the
rows returned by the select. Still all working fine. Next, I select a
single row from the search query (selected by mouse click on the
dbgrid row) and grab all the data in the row (all 4 table
fields) and put it in a global record variable. Then I hide the lookup
form (can't close it yet until
the calling form gets the data.) Thanks for reading this far. Now, to
the problem.

I want to use the returned data from the search dbgrid to position the
row or cursor in the
original query. This would have the affect of selecting the 'found'
row and filling all the data
aware components (dbmemos, dbedits etc) with the searched for record.
From that point the
user can still continue to use the dbnavigator to go forward or
backward in the query.
I don't know how to set the row in the original query. Do I have to
loop thru the whole query
and compare each field against my 'found' data to see if that is the
correct position, and then just exit the loop, leaving the query
positioned at that spot???

I've searched 32 pages of this forum and on the web for days without
finding an answer. Please
help.

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Marc · 2009-08-31 18:22

dataset.locate

btw, if you ise IDs as an unique key for your rows, you only have to
lookup this id (and not seachting for a set of maybe unique values)

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mrmikehicks · 2009-08-31 19:56

Thanks Marc, after a bit more reading about the locate method, I came
up
with a solution that puts the original query where it should be:

    if not (dmr.zquery_item.Locate('ID', item_id_str, [])) then begin
      dmr.zquery_item.SQL.Clear;
      dmr.zquery_item.SQL.Add('Seletc * from item');
      dmr.zquery_item.Open;
    end;
    dmr.zquery_item.Refresh;

You were correct, in that the ID (primary key) field was the only
field I
needed to search for, so for this part of the application, I didn't
use the
data in the other 3 fields.
Thanks again, a little nudge in the right direction does wonders.

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mrmikehicks · 2009-08-31 20:01

On second thought, not sure if I need to run the 'select * from item'
again
if the primary key is not found. Not sure where that would leave the
pointer after a failed locate method. And anyway, if I can't locate
the primary key, things would be really more screwed up than I
realize.