lasarus_compotents/RXLib/.svn/pristine/b9/b9a8536b44a0b5ca99a5707ee68e89271fcbeba2.svn-base

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{ RxDBGrid sort engine module for FBDataSet
Copyright (C) 2011 BugMaker from freepascal.ru
This library is free software; you can redistribute it and/or modify it
under the terms of the GNU Library General Public License as published by
the Free Software Foundation; either version 2 of the License, or (at your
option) any later version with the following modification:
As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent modules,and
to copy and distribute the resulting executable under terms of your choice,
provided that you also meet, for each linked independent module, the terms
and conditions of the license of that module. An independent module is a
module which is not derived from or based on this library. If you modify
this library, you may extend this exception to your version of the library,
but you are not obligated to do so. If you do not wish to do so, delete this
exception statement from your version.
This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License
for more details.
You should have received a copy of the GNU Library General Public License
along with this library; if not, write to the Free Software Foundation,
Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
}
unit exsortsql;
{$mode objfpc}{$H+}
interface
uses
Classes, SysUtils, DB, RxDBGrid;
type
{ TSQLQuerySortEngine }
TSQLQuerySortEngine = class(TRxDBGridSortEngine)
public
procedure Sort(FieldName: string; ADataSet:TDataSet; Asc:boolean; SortOptions:TRxSortEngineOptions);override;
procedure SortList(ListField: string; ADataSet: TDataSet; Asc: array of boolean; SortOptions: TRxSortEngineOptions); override;
end;
implementation
uses SQLDB, RegExpr, strUtils;
procedure TSQLQuerySortEngine.Sort(FieldName: string; ADataSet: TDataSet;
Asc: boolean; SortOptions: TRxSortEngineOptions);
begin
SortList(FieldName,ADataSet,Asc,SortOptions);
end;
procedure TSQLQuerySortEngine.SortList(ListField: string; ADataSet: TDataSet;
Asc: array of boolean; SortOptions: TRxSortEngineOptions);
var
S:string;
i, C:integer;
cmd:string;
strLen:Integer;
RegExpr: TRegExpr;
Mask:String;
OldParams:TParams;
begin
if not (Assigned(ADataSet) and ADataset.Active) then exit;
S:='';
C:=Pos(';', ListField);
i:=0;
while C>0 do
begin
if S<>'' then S:=S+',';
S:=S + Copy(ListField, 1, C-1);
Delete(ListField, 1, C);
if (i<=High(Asc)) and (not Asc[i]) then
S:=S + ' DESC';
C:=Pos(';', ListField);
inc(i);
end;
if ListField<>'' then
begin
if S<>'' then S:=S+',';
S:=S + ListField;
if (i<=High(Asc)) and (not Asc[i]) then
S:=S + ' DESC';
end;
OldParams:=TParams.Create;
OldParams.Assign((ADataSet as TSQLQuery).Params);
cmd:=(ADataSet as TSQLQuery).SQL.Text;
strlen:=length(cmd);
//Регулярное выражение позволяет найти уже имеющуюся конструкцию ORDER BY,
//если она написана одной строкой, и между словами не понапихали комментариев :)
//Работоспособные примеры:
//ORDER BY FIELD1, FIELD2 DESC, FIELD100500
//oRdeR bY fielD1 , FiElD2,FieLD100500 DESC
//Неработоспособный:
//ORDER BY FIELD1,
//FIELD2,
//FIELD100500
mask:='(?i)(^|\s)\s*order\s+by\s+\S+\.?\S*(\s+desc)?\s*(,\s*\S+\.?\S*(\s+desc)?(^|s*))*';
with TRegExpr.Create do begin
Expression := mask;
if Exec(cmd) then begin
s:=LeftStr(cmd,MatchPos[0]-1)
+slinebreak+'order by '
+s+slineBreak
+RightStr(cmd, strlen-MatchPos[0]-MatchLen[0]+1);
end
else
s:=cmd+slinebreak+'order by '+s+slineBreak;
ADataSet.Active:=False;
(ADataSet as TSQLQuery).SQL.Text:=s;
(ADataSet as TSQLQuery).Params.Assign(OldParams);
OldParams.Free;
ADataSet.Active:=True;
Free;
end;
end;
initialization
RegisterRxDBGridSortEngine(TSQLQuerySortEngine, 'TSQLQuery');
end.