事务 c#

事务->:事务是恢复和并发控制的基本单位

              ->事务具有四个特性：原子性、隔离性、一致性、持久性。这四个特性通常称为ACID

       Begin transaction/tran   --开始事务

       Commit transaction/tran  --提交事务

       Rollback transaction/tran  --回滚事务

Select * from userinfo with(nolock)       --表示在查询的时候不加共享锁

一个简单的小案例

using (SqlConnection conn = new SqlConnection(connStr))

            {

                conn.Open();

                //开始事务

                SqlTransaction ts = conn.BeginTransaction();

                try

                {

                    string sql = "insert into BuyRecord(UID,PID,BRNum,BRTime) values(@uid,@pid,@num,@time)";

                    SqlCommand cmd = new SqlCommand(sql, conn);

                    cmd.Transaction = ts;

                    cmd.Parameters.AddWithValue("@uid", brm.UID);

                    cmd.Parameters.AddWithValue("@pid", brm.PID);

                    cmd.Parameters.AddWithValue("@num", brm.BRNum);

                    cmd.Parameters.AddWithValue("@time", DateTime.Now);

                    cmd.ExecuteNonQuery();

                    string uptsql = " update ProductInfo set ProductNum=ProductNum-@buyNum where ProductID=@id";

                    cmd.CommandText = uptsql;

                    cmd.Parameters.AddWithValue("@buyNum", brm.BRNum);

                    cmd.Parameters.AddWithValue("@id", brm.PID);

                    cmd.ExecuteNonQuery();

 

                    ts.Commit();

                    return 1;

                }

                catch (Exception)

                {

                    ts.Rollback();

                    return -1;

                    throw;

                }