.net和sql中的事务写法

sql server中使用事务

银行转账的例子，用户0001向用户0002转帐10000元

	begin transaction --开始
	begin try
		update NUser set Money = Money - 10000 where UserID='0001'
		raiserror('更新有错误',16,1)		
		update NUser set Money = Money + 10000 where UserID='0002'
		commit --提交
	end try
	begin catch
		if @@TRANCOUNT >0 and @@error >0
			select ERROR_LINE(),ERROR_MESSAGE(),ERROR_SEVERITY(),ERROR_STATE()
			rollback--回滚
	end catch

C#编码实现事务

SqlTransaction sqltran = null;
            try
            {
                //1 获取界面用户输入数据
                string userid_out = textBoxOut.Text.Trim();//转出用户账号
                string userid_in = textBoxIn.Text.Trim();//转入用户账号
                decimal amt = Convert.ToDecimal(textBoxAmt.Text.Trim());
                //2 打开数据库连接对象
                string connstr = "server=(local)\\SqlExpress;Integrated Security=SSPI;database = DB";
                SqlConnection sqlconn = new SqlConnection();
                sqlconn.ConnectionString = connstr;
                if (sqlconn.State != ConnectionState.Open)
                {
                    sqlconn.Open();
                    sqltran = sqlconn.BeginTransaction();//开始事务
                }

                //3 转入账户金额处理
                SqlParameter[] cmdparams_in = new SqlParameter[]{
                    new SqlParameter("@UserID",userid_in),
                    new SqlParameter("@Amt",amt)
                };
                SqlCommand sqlcmd_in = new SqlCommand();
                sqlcmd_in.Connection = sqlconn;
                sqlcmd_in.CommandText = "update NUser set money = money + @Amt where UserID = @UserID";
                sqlcmd_in.CommandType = CommandType.Text;
                sqlcmd_in.Parameters.AddRange(cmdparams_in);
                sqlcmd_in.Transaction = sqltran;
                int in_rows = sqlcmd_in.ExecuteNonQuery();

                if (in_rows == 0)
                {
                    throw new Exception("转入账户不存在。");
                }

                //4 转出账户金额处理
                SqlParameter[] cmdparams_out = new SqlParameter[]{
                    new SqlParameter("@UserID",userid_out),
                    new SqlParameter("@Amt",amt)
                };
                SqlCommand sqlcmd_out = new SqlCommand();
                sqlcmd_out.Connection = sqlconn;
                sqlcmd_out.CommandText = "update NUser set money = money - @Amt where UserID = @UserID";
                sqlcmd_out.CommandType = CommandType.Text;
                sqlcmd_out.Parameters.AddRange(cmdparams_out);
                sqlcmd_out.Transaction = sqltran;

                int out_rows = sqlcmd_out.ExecuteNonQuery();
                if (out_rows == 0)
                {
                    throw new Exception("转出账户不存在。");
                }
                sqltran.Commit(); //提交事务
                //5 提示处理结果
                MessageBox.Show("转账成功。");
            }
            catch (Exception ex)
            {
                if (sqltran != null)
                {
                    sqltran.Rollback();
                }
                MessageBox.Show(ex.Message);
            }