事务出错the transaction isolation level must be dirty read for local databases

Question

事务出错the transaction isolation level must be dirty read for local databases
Query2.close;
         Query2.Sql.clear;
         Query2.SQL.Add('insert into userr (usernam,psw) values (:usname,:psww)');
         Query2.ParamByName('usname').asstring:=ComboBox1.Text;
         Query2.ParamByName('psww').asstring:=pssword;
         //psword:= Query1.FieldValues['psw'];
         //psw:= form1.UncrypKey(psw,'123456');
         //psword.Text:=psw;
         Database1.StartTransaction; //开始事务控制
           try
             Query2.ExecSQL; //开始插入记录
             Database1.Commit; //提交事务
           except
             Query2.Free; //如果出错首先将Query Free掉
             Database1.RollBack; //回退事务
             raise; //重新引发异常,以通知用户
           end;
           Query2.free;

Answer 1

procedure TForm1.Button1Click(Sender: TObject);
var
  Query2 : TQuery;
begin
  Query2 := TQuery.Create(nil);
  Query2.DatabaseName := 'db';
  try
    database1.StartTransaction;
    try
      with Query2 do
      begin
        close;
        sql.Clear;
        sql.Add('insert into userr (usernam,psw) values (:usname,:psww)');
        ParamByName('usname').asstring:=edit1.Text;
        ParamByName('psww').asstring:=edit2.text;
        ExecSql;
      end;
      database1.Commit;
    except
      database1.Rollback;
      raise;
      {*
      on e:exception do
      begin
        Database1.RollBack; //回退事务
        showmessage(e.Message);
      end;
      *}
    end;
  finally
    Query2.Free;
  end;
end;

Answer 2

         try
         if Not Database1.InTransaction then
            Database1.StartTransaction; //开始事务控制
         Query2.close;
         Query2.Sql.clear;
         Query2.SQL.Add('insert into userr (usernam,psw) values (:usname,:psww)');
         Query2.ParamByName('usname').asstring:=ComboBox1.Text;
         Query2.ParamByName('psww').asstring:=pssword;
         //psword:= Query1.FieldValues['psw'];
         //psw:= form1.UncrypKey(psw,'123456');
         //psword.Text:=psw;
          Query2.ExecSQL; //开始插入记录
            Database1.Commit; //提交事务
           except
             begin
               Query2.Free; //如果出错首先将Query Free掉
                 Database1.RollBack; //回退事务
                 raise; //重新引发异常,以通知用户
               end;
           end;
           Query2.free;

Answer 3

try this:procedure TForm1.Button1Click(Sender: TObject);
var
  Query:TQuery;
begin
  Query:=TQuery.Create(nil);
  Query.DatabaseName:='Test';
  try
  database1.StartTransaction;
  try
  with Query do
  begin
  close;
  sql.Clear;
  sql.Add('insert into Logininfo (usernae,pwd) values (:username,:passwords)');
  ParamByName('username').asstring:=edit1.Text;
  ParamByName('passwords').asstring:=edit2.text;
  ExecSql;
  end;
  database1.Commit;
  except
  database1.Rollback;
  raise;
  end;
  finally
  Query.Free;
  end;
end;

Answer 4

我是用Database Desktop做的userr.db数据表，放在程序的db文件夹下，程序放在ck文件夹下的aa文件夹下，ck文件夹下有二个文件夹，aa和db，db放着userr.db，aa放着程序，我的路径是
..\db
不用事务，3楼的可以写入数据，用了事务就还是出上面的错误，说是数据库要用本地的数据库，怎么回事啊。

Answer 5

database1.TransIsolation:= tiDirtyRead ;
错误的提示是意思就是，让本地的数据库的脏读是第二级，就是让database1.TransIsolation赋值为tiDirtyRead ;