Solved

Multiple DB filtering

Posted on 2002-04-14
13
208 Views
Last Modified: 2010-04-04
I use next code to filter my table :

table1.filter := 'GRUPA= ''A05AA02'' or GRUPA= ''A06AD11'' or GRUPA= ''A07AA11'' or GRUPA= ''C03AA03'' or GRUPA= ''C03CA01'' or GRUPA= ''C03DA01'' or GRUPA= ''C07AA05'' or GRUPA= ''H02AB04'' or GRUPA= ''J01CA01'' or GRUPA= ''J01MA02'' or GRUPA= ''J01MA06'' or GRUPA= ''J05AF05'' or GRUPA= ''L04AX01'' or GRUPA= ''V03AC01'' or GRUPA= ''H02AB07''';

table1.filtered := true;

The problem is that my string is longer than 256 characters and I get an error message when compile the project.

Any suggestion how can I step over this problem?
0
Comment
Question by:ginsonic
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 4
  • 2
  • +3
13 Comments
 
LVL 3

Accepted Solution

by:
marcoszorrilla earned 100 total points
ID: 6940469
Split the string
you must load for example S1 with 250 characters for example and S2 with the rest

Var
S1,S2:String

Table1.filter:=S1+S2
Table1.Filtered:=True;

Best regards.
Marcos.
0
 
LVL 15

Expert Comment

by:simonet
ID: 6940857
Try this:

table1.filter := '( GRUPA IN (''A05AA02'', ''A06AD11'', ''A07AA11'', ''C03AA03'' , ''C03CA01'', ''C03DA01'', ''C07AA05'', ''H02AB04'', ''J01CA01'', ''J01MA02'', ''J01MA06'', ''J05AF05'', ''L04AX01'', ''V03AC01'', ''H02AB07''))';

table1.filtered := true;



if the code above works it will not only sole the large string problem, but the filtering will also be faster.

Yours,

Alex
0
 
LVL 10

Expert Comment

by:Jacco
ID: 6941212
It also works when splitting up the string in your code without the use of variables:

Table1.Filter := 'first part < 255 charachters' +
  'second part < 255 charachters' +
  'third part < 255 charachters' +
  'etc...';

Regards Jacco
0
Technology Partners: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

 
LVL 10

Expert Comment

by:Jacco
ID: 6941213
With complex filters that change often it might also be better to use the OnFilterRecord event.

Regards Jacco
0
 
LVL 27

Expert Comment

by:kretzschmar
ID: 6941260
i would use a tquery instead a ttable,
if there are such complex (where) clauses
affected

meikl ;-)
0
 
LVL 9

Author Comment

by:ginsonic
ID: 6941802
kretzschmar can you tell me more ? Untill now I have used just table+dataSource+DBGrid in my projects :(

I wish to say that I have couple situations when I use ~50 conditions for filtering .
0
 
LVL 9

Author Comment

by:ginsonic
ID: 6941835
simonet , your suggestion get me an error message alike 'Operation not applicable' for this.
0
 
LVL 27

Expert Comment

by:kretzschmar
ID: 6941895
guessing simonets suggestion
is not supported by your database :-(

you can do the same as the ttable with a tquery+tdatasource+tdbgrid+tupdatesql (as updateobject of the tquery, if editing, deletes and inserts may possible)

lets say we have a sql-statement like

select * from atable

this shows all entries of atable

if you want to filter, you modify the sql-statement like
select * from atable where condition

you can do this on the fly like

function get_filter_sql(atable, awhereclause : String)
const
  sqltextnowhere := 'select * from atable %s';
  sqltextwhere := sqltextnowhere+' where %s';
begin
  if awhereclause = '' then
   result := format(sqltextnowhere,[atable])
  else
   result := format(sqltextwhere,[atable,awhereclause])
end;

usage sample

query1.close;
query1.sql.text := get_filter_sql(yourtable,yourfilter);
query1.open;

hope this helps

meikl ;-)
0
 
LVL 9

Author Comment

by:ginsonic
ID: 6942407
Look a little more complicated . What's the difference between my filtering and the query's one ?
What gain using a query ?
0
 
LVL 27

Expert Comment

by:kretzschmar
ID: 6942506
usual on sql-databases it is recommended to work with queries
-lower overhead
-faster results
-you can order the result by any field(s) with an order by clause

there should be no difference
in the result of the query
and the filtering

in your case, you use dbase,
i guess from previous q's,
it is a workaround

meikl ;-)
0
 
LVL 4

Expert Comment

by:nestorua
ID: 6942918
HI, ginsonic,
If you don't want to use TQuery component and use TTable one
for your purpose it would be reasonable to use OnFilterRecord
event.
Create TStringList, fill it with your specific strings
('A05AA02', ...) and write the following
Accept:=StringListName.IndexOf(GRUPA.AsString)<>-1.
That's all.
Sincerely,
Nestorua.
0
 
LVL 27

Expert Comment

by:kretzschmar
ID: 6943067
yep, this may also a solution, Nestorua
0
 
LVL 9

Author Comment

by:ginsonic
ID: 6955969
I choice a different way to step over my problem ( not proposed here ) but this is the first working solution .

Thanks to all experts,

Nick aka ginsonic
0

Featured Post

Secure Your Active Directory - April 20, 2017

Active Directory plays a critical role in your company’s IT infrastructure and keeping it secure in today’s hacker-infested world is a must.
Microsoft published 300+ pages of guidance, but who has the time, money, and resources to implement? Register now to find an easier way.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

This article explains how to create forms/units independent of other forms/units object names in a delphi project. Have you ever created a form for user input in a Delphi project and then had the need to have that same form in a other Delphi proj…
Hello everybody This Article will show you how to validate number with TEdit control, What's the TEdit control? TEdit is a standard Windows edit control on a form, it allows to user to write, read and copy/paste single line of text. Usua…
Although Jacob Bernoulli (1654-1705) has been credited as the creator of "Binomial Distribution Table", Gottfried Leibniz (1646-1716) did his dissertation on the subject in 1666; Leibniz you may recall is the co-inventor of "Calculus" and beat Isaac…
In a recent question (https://www.experts-exchange.com/questions/29004105/Run-AutoHotkey-script-directly-from-Notepad.html) here at Experts Exchange, a member asked how to run an AutoHotkey script (.AHK) directly from Notepad++ (aka NPP). This video…

749 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question