Filter syntax
lazarus / 63-Database

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johnmc · 2020-01-12 14:24

I have been trying to find some documenation regarding the syntax of
the filter string used to filter a dataset, hitting F1 brings up only
a brief description. Where can I find a complete description?

The best that I can come up with is the wiki https://wiki.lazarus.free
pascal.org/Lazarus_Tdbf_Tutorial#Index.2Ffilter_on_strings

Was there some sort of software specification writen for this if so
where would I find it?

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howardpc · 2020-01-12 14:30

Are you asking specifically about the Lazarus/FPC implementation of
TDbf, or some other dataset descendant?

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johnmc · 2020-01-12 14:48

I am using Sqlite3, so that would be my preference if it makes any
difference.

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balazsszekely · 2020-01-12 17:35

If you're using TSQLQuery, which is a TCustomBufDataset descendent, 
the solution is quite simple: create an OnFilterRecord for the Query,
then:
Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i procedure
TForm1.SQLQuery1FilterRecord(DataSet: TDataSet; var Accept:
Boolean);begin  Accept := SQLQuery1.FieldByName('FIRSTNAME').AsString
= 'John';end; The code is self explanatory I guess, if not please let
us know.

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johnmc · 2020-01-12 20:47

GetMem I was using TDataSet.Filter and want more info on the format
and syntax of the filter string.

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i      
myFilter := 'Country = ' + QuotedStr(DBGrid1.SelectedField.AsString); 
    SQLQuery.filter := myFilter;      SQLQuery.Filtered := True;