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Lock table and update help me
Posted: Fri 30 Nov 2012 08:20
by alicinar
The following code does not work.
How can I do?
OraQuery1.LockMode:=lmLockDelayed;
OraQuery1.sql.text:='select number_column from tableNAme where rownum=1';
OraQuery1.Open;
OraQuery1.Lock;
OraQuery1.SQLUpdate.Text:='update tableName set number_column=number_column+1';
OraQuery1.Post;
OraQuery1.UnLock;
Re: Lock table and update help me
Posted: Fri 30 Nov 2012 09:54
by AlexP
Hello,
If you want to modify records in the table using your query, you should invoke the TOraQuery.Edit method as well as assign the SQLUpdate.Text value. In addition, your sample has no sense, as after invoking the Lock method, only one record will be Locked, and your UPDATE will be applied to all the table. Please describe your issue in more details, and we will try to provide you with an appropriate sample.
Re: Lock table and update help me
Posted: Fri 30 Nov 2012 10:09
by alicinar
My table script(one table one columd one row)(not use oracle sequence):
Code: Select all
CREATE TABLE UOPUM_NUMARA(DEGER NUMBER)
Code: Select all
object Form1: TForm1
Left = 0
Top = 0
Caption = 'Form1'
ClientHeight = 159
ClientWidth = 341
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'Tahoma'
Font.Style = []
OldCreateOrder = False
PixelsPerInch = 96
TextHeight = 13
object Label1: TLabel
Left = 56
Top = 64
Width = 31
Height = 13
Caption = 'Label1'
end
object Label2: TLabel
Left = 56
Top = 96
Width = 31
Height = 13
Caption = 'Label2'
end
object Button1: TButton
Left = 40
Top = 16
Width = 75
Height = 25
Caption = 'Read'
TabOrder = 0
OnClick = Button1Click
end
object Button2: TButton
Left = 236
Top = 16
Width = 75
Height = 25
Caption = 'Unlock'
TabOrder = 1
OnClick = Button2Click
end
object Button3: TButton
Left = 136
Top = 16
Width = 75
Height = 25
Caption = 'Update'
TabOrder = 2
OnClick = Button3Click
end
object OraQuery1: TOraQuery
SQLUpdate.Strings = (
'UPDATE UOPUM_NUMARA SET DEGER = DEGER+1;')
CachedUpdates = True
LockMode = lmLockDelayed
Left = 160
Top = 56
end
object OraQuery2: TOraQuery
SQL.Strings = (
'select deger from uopum_numara where rownum=1')
Left = 248
Top = 56
end
end
Code: Select all
unit Unit1;
interface
uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Data.DB, MemDS, DBAccess,
Ora;
type
TForm1 = class(TForm)
OraQuery1: TOraQuery;
Button1: TButton;
Button2: TButton;
Label1: TLabel;
Button3: TButton;
OraQuery2: TOraQuery;
Label2: TLabel;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure Button3Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure TForm1.Button1Click(Sender: TObject);
begin
OraQuery1.Close;
OraQuery1.SQL.Text:='SELECT DEGER FROM UOPUM_NUMARA';
OraQuery1.Open;
OraQuery1.Lock;
Label1.Caption:=OraQuery1.Fields.Fields[0].AsString;
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
OraQuery1.UnLock;
end;
procedure TForm1.Button3Click(Sender: TObject);
begin
OraQuery1.LockMode:=lmLockDelayed;
OraQuery1.Post;
OraQuery1.Close;
OraQuery2.Close;
OraQuery2.Open;
Label2.Caption:=OraQuery2.Fields.Fields[0].AsString;
end;
end.
Re: Lock table and update help me
Posted: Fri 30 Nov 2012 12:20
by AlexP
Hello,
in your case, there is no need to use two TOraQuery's and modify the SQLUpdate property, the following will be enough:
Code: Select all
OraQuery1.LockMode := lmLockDelayed;
OraQuery1.SQL.Text := 'SELECT DEGER FROM UOPUM_NUMARA';
OraQuery1.Open;
OraQuery1.Edit;
OraQuery1.FieldByName('DEGER').AsInteger := OraQuery1.FieldByName('DEGER').AsInteger + 1;
OraQuery1.Post;
Re: Lock table and update help me
Posted: Fri 30 Nov 2012 13:55
by alicinar
thanks alexp.