TMemoField instead of TStringField.
lazarus / 16-Databases

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BSaidus · 2025-09-29 14:18

Hello.
I use TZQuery from ZeosDBO and I have a an SQLITE View witch is an SQL
aggregation of some fields from different tables.
Say
   vtmp_1 is a view, and
   f1: a VARCHAR field,
   f2: a VARCHAR field,
   f3: a VARCHAR field,
   f4: an aggregated field => CAST(('aa_'||LOWER(REPLACE(name, ' ',
'_'))||'="'||fname||'"') AS VARCHAR) AS ENAME
When I use an SQL SELECT Statement in a ZQuery, I got "f4" as
TMemoField
In every cases, Code: SQL  [Select][+][-]window.onload =
function(){var x1 = document.getElementById("main_content_section");
if (x1) { var x = document.getElementsByClassName("geshi");for (var i
= 0; i SELECT  f1,        f2,        f3,        f4   FROM vtemp_1;  
 SELECT  f1,        f2,        f3,        CAST(f4 AS VARCHAR) AS f4 
 FROM vtemp_1; 
So Is there any solution for this, I need it to use this fied as a
Lookup field in TDBLookupComboBox ( Now it display (memo) as content
).

Thank you.

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Zvoni · 2025-09-29 14:28

IIRC, you have to implement the OnGetText-Event for the Field

This is similiar to your problem:
https://forum.lazarus.freepascal.org/index.php/topic,69567.msg540683.h
tml#msg540683

Edit: an alternative approach might be to use generated columns from
the get go instead of concatenating it in the query/view
But this depends, if the used fields for f4/ename are from the same
table

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BSaidus · 2025-09-29 16:58

Quote from: Zvoni on September 29, 2025, 04:28:15 pmIIRC, you have to
implement the OnGetText-Event for the Field

This is similiar to your problem:
https://forum.lazarus.freepascal.org/index.php/topic,69567.msg540683.h
tml#msg540683

Edit: an alternative approach might be to use generated columns from
the get go instead of concatenating it in the query/view
But this depends, if the used fields for f4/ename are from the same
table

Thanks @Zvoni.
It works well, I will investigate the 2nd method.
Thnks again.

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Zvoni · 2025-09-30 06:28

Quote from: BSaidus on September 29, 2025, 06:58:43 pmThanks @Zvoni.
It works well, I will investigate the 2nd method.
Thnks again.
As for the second (alternative) Approach (Generated Columns):
Could you post the CREATE-Statement for that View?

The crucial part is this
Quote f4: an aggregated field => CAST(('aa_'||LOWER(REPLACE(name, ' ',
'_'))||'="'||fname||'"') AS VARCHAR) AS ENAME
"name" and "fname": Are these two fields in the same table?
If yes, then i would definitely go with generated Columns instead of
"calculating" it via query and then Type-Casting it from here to
Moscow
If no (they are in separate tables), then your current solution is the
only viable way