SqlConnection connnn = new SqlConnection(strcon); connnn.Open(); string updatStr = "update tbook set snum=snum-1 where ISBN='" + textBox3.Text + "'"; DataSet das = new DataSet(); SqlDataAdapter data = new SqlDataAdapter(); das.Tables.Clear(); SqlCommand updatComm = new SqlCommand(updatStr, connnn); data.UpdateCommand = updatComm; data.UpdateCommand.ExecuteNonQuery();
假设你的数据表是这样设计的 CREATE TABLE [dbo].[books] ( [book_id] [int] NOT NULL, [book_num] [int] NOT NULL DEFAULT(0), -- ... ) #using System.Data #using System.Data.Sql //...SqlConnection conn = new SqlConnection([你的连接字符串]) conn.Open();SqlCommand cmd = new SqlCommand("UPDATE books SET book_num=book_num-1 WHERE book_id=@book_id"); cmd.Parameters.Add("@book_id",SqlDbType.Int).Value=[你获取book_id]int ret = cmd.ExcuteNonQuery();if(ret>0) ;//更改成功 else ;//更改失败,没有对应book_id//...conn.Close(); conn.Dispose();
connnn.Open();
string updatStr = "update tbook set snum=snum-1 where ISBN='" + textBox3.Text + "'";
DataSet das = new DataSet();
SqlDataAdapter data = new SqlDataAdapter();
das.Tables.Clear();
SqlCommand updatComm = new SqlCommand(updatStr, connnn);
data.UpdateCommand = updatComm;
data.UpdateCommand.ExecuteNonQuery();
CREATE TABLE [dbo].[books]
(
[book_id] [int] NOT NULL,
[book_num] [int] NOT NULL DEFAULT(0),
-- ...
)
#using System.Data
#using System.Data.Sql
//...SqlConnection conn = new SqlConnection([你的连接字符串])
conn.Open();SqlCommand cmd = new SqlCommand("UPDATE books SET book_num=book_num-1 WHERE book_id=@book_id");
cmd.Parameters.Add("@book_id",SqlDbType.Int).Value=[你获取book_id]int ret = cmd.ExcuteNonQuery();if(ret>0) ;//更改成功
else ;//更改失败,没有对应book_id//...conn.Close();
conn.Dispose();