Создание автоинкрементного поля SQL запросом?

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Code:

{

Lets say that we wish to create a fallawing number (Autoincrese) of an item,

without using the AutoIncrese filed.

This is usfull when for example there is more users from the same IP that log

in or any other things that you wish.

 

This example will show you how to do it with some checking of filled data,

but it can be done anyway you wish.

 

You need a Table with at least 2 fileds with number casting, and a TQUERY component.

}

 

 

function TForm1.GetNextNumber : integer;

begin

qryMain.Active := False;

qryMain.SQL.Clear;

qryMain.SQL.Add('Select Max(FieldToIncrease) from tblMain where (Cheking >=1);');

qryMain.Active := True; //We executed the query

 

if qryMain.RecordCount >= 0 then

result := qryMain.FieldByName('FieldToIncrese').AsInteger +1;

else result := 1;

end;

 

...

 

procedure TForm1.SetNextNumber;

begin

//You must first see if the table is in insert/update mode before using this procedure.

tblMain.FieldByName('FieldToIncrese').AsInteger := GetNextNumber;

end;

 

 

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