FireDAC 数据库访问

uses
  FireDAC.Comp.Client, FireDAC.Comp.Dataset, FireDAC.Stan.Param;

var
  Conn: TFDConnection;
  Query: TFDQuery;
begin
  Conn := TFDConnection.Create(nil);
  Query := TFDQuery.Create(nil);
  try
    Conn.DriverName := 'SQLite';
    Conn.Params.Database := 'app.db';
    Conn.Connected := True;

    Query.Connection := Conn;

    // Parameterized query (prevents SQL injection)
    Query.SQL.Text := 'SELECT * FROM users WHERE age > :min_age ORDER BY name';
    Query.ParamByName('min_age').AsInteger := 18;
    Query.Open;

    // Iterate
    while not Query.Eof do
    begin
      ShowMessage(Query.FieldByName('name').AsString + ': ' +
                  Query.FieldByName('age').AsString);
      Query.Next;
    end;

    // Execute (no result set)
    Query.SQL.Text := 'UPDATE users SET active = 1 WHERE id = :id';
    Query.ParamByName('id').AsInteger := 42;
    Query.ExecSQL;
  finally
    Query.Free;
    Conn.Free;
  end;
end;