para luineumann, urgente

aqui vai o exemplo

copie o texto desde o primeiro *-*-*-*-* até o segundo *-*-*-*-*-* e
salve como unit1.pas
copie o texto desde o segundo *-*-*-*-* até o terceiro -*-* e salve
como unit1.dfm

abra um projeto novo e adicone esta unit

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// unit1.pas

unit Unit1;

interface

uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms,
Dialogs,
ExtCtrls, DBCtrls, StdCtrls, Mask, Grids, DBGrids, Db, DBTables;

type
TForm1 = class(TForm)
tb1: TTable;
ds1: TDataSource;
qr1: TQuery;
tb1Apelido: TStringField;
DBGrid1: TDBGrid;
DBEdit1: TDBEdit;
DBNavigator1: TDBNavigator;
procedure DBEdit1Exit(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure FormClose(Sender: TObject; var Action: TCloseAction);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.DBEdit1Exit(Sender: TObject);
begin
if tb1.State <> dsInsert // não é inclusão
then Exit;
qr1.close;
qr1.sql.clear;
qr1.sql.add(´Select Apelido´);
qr1.sql.add(´from ´ + tb1.tableName);
qr1.sql.add(´where (apelido = ´
+ quotedstr(tb1apelido.value)
+ ´)´);
qr1.open;
if qr1.recordcount = 0
then begin
qr1.close;
exit;
end;

messagedlg(´Este apelido já existe´,
mtError, [mbOk], 0);
dbEdit1.SetFocus;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
tb1.open;
end;

procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
begin
tb1.close;
end;

end.

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// unit1.dfm

object Form1: TForm1
Left = 192
Top = 121
Width = 696
Height = 480
Caption = ´Form1´
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -13
Font.Name = ´MS Sans Serif´
Font.Style = []
OldCreateOrder = False
OnClose = FormClose
OnCreate = FormCreate
PixelsPerInch = 120
TextHeight = 16
object DBGrid1: TDBGrid
Left = 112
Top = 112
Width = 320
Height = 120
DataSource = ds1
TabOrder = 0
TitleFont.Charset = DEFAULT_CHARSET
TitleFont.Color = clWindowText
TitleFont.Height = -13
TitleFont.Name = ´MS Sans Serif´
TitleFont.Style = []
end
object DBEdit1: TDBEdit
Left = 88
Top = 312
Width = 121
Height = 24
DataField = ´Apelido´
DataSource = ds1
TabOrder = 1
OnExit = DBEdit1Exit
end
object DBNavigator1: TDBNavigator
Left = 208
Top = 248
Width = 240
Height = 25
DataSource = ds1
TabOrder = 2
end
object tb1: TTable
DatabaseName = ´Lna_Veiculos_Teste´
TableName = ´tbSiapa_Veiculos.DB´
Left = 24
Top = 72
object tb1Apelido: TStringField
FieldName = ´Apelido´
Size = 10
end
end
object ds1: TDataSource
DataSet = tb1
Left = 96
Top = 64
end
object qr1: TQuery
DatabaseName = ´Lna_Veiculos_Teste´
Left = 192
Top = 48
end
end

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