Duvidas Delphi7 X ADO X SQL SERVER 2000

unit Unit1;

interface

uses
  SysUtils, Classes, DB, ADODB;

type
  TDataModule1 = class(TDataModule)
    ADOConnection1: TADOConnection;
  private
    { Private declarations }
  public
    { Public declarations }
    function NovoSeq(Tabela, Campo: string; Condicao: string): integer; overload;
    function NovoSeq(Tabela, Campo: string): integer; overload;    
  end;

implementation

{$R *.dfm}

function TDataModule1.NovoSeq(Tabela, Campo: string): integer;
begin
  Result := NovoSeq(Tabela, Campo, ´´);
end;

function TDataModule1.NovoSeq(Tabela, Campo: string; Condicao: string): integer;
var
  DataSet: TADODataSet;
begin
  DataSet := TADODataSet.Create(nil);
  try
    if Condicao <> ´´ then
      Condicao := ´ WHERE ´ + Condicao;
    DataSet.Connection := Self.ADOConnection1;
    DataSet.Close;
    DataSet.CommandText :=
      ´SELECT MAX(´ + Campo + ´) AS ULTIMO ´ +
      ´FROM ´ + Tabela + Condicao;
    DataSet.Open;

    if DataSet.FieldByName(´ULTIMO´).IsNull then
      Result := 1
    else
      Result := DataSet.FieldByName(´ULTIMO´).AsInteger + 1;
    DataSet.Close;
    DataSet.Connection := nil;
  finally
    FreeAndNil(DataSet);
  end;
end;

end.

CREATE TABLE TESTE
(
  CAMPO INT IDENTITY NOT NULL,
  CAMPO2 VARCHAR(50),  
  PRIMARY KEY (CAMPO)
)