Well, the ExecuteNonQuery method is there for statements for changing data, ie. DELETE / UPDATE /INSERT, and the returned value are the number of rows affected by that statement. When checking the documentation we can see that there are some conditions that return -1. ...
Well, the ExecuteNonQuery method is there for statements for changing data, ie. DELETE / UPDATE /INSERT, and the returned value are the number of rows affected by that statement. When checking the documentation we can see that there are some conditions that return -1. ...
前面一篇文章,我们介绍了如何在c#中对数据库进行更新操作。主要是利用SqlCommand 对象的ExecuteNonQuery方法。 这篇文章介绍,如何进行查询操作。本文给出的例子仍然是针对sql server数据库的。对于其它数据库(源),区别只是引入的部门api的不同,但流程和方法是一样的。
cmd.Parameters.Add("@Id", SqlDbType.Int); //添加参数,说明类型 cmd.Parameters["@Id"].Value = 1; //设置参数值 conn.Open(); //打开连接 int i = cmd.ExecuteNonQuery(); //执行命令,ExecuteNonQuery由名称看出,只能用于非查询语句 conn.Close(); //关闭连接 Console.WriteLine(i); //输出影响行...
BeginExecuteNonQuery() Initiates the asynchronous execution of the Transact-SQL statement or stored procedure that is described by this SqlCommand. BeginExecuteNonQuery(AsyncCallback, Object) Initiates the asynchronous execution of the Transact-SQL statement or stored procedure that is described by this...
cmd.CommandType = commandType; cmd.Parameters.AddRange(parameters); conn.Open(); return cmd.ExecuteNonQuery(); } } } // Set the connection, command, and then execute the command and only return one value. public static Object ExecuteScalar(String connectionString, String commandText, CommandType...
由于此重载不支持回调过程,因此开发人员必须使用 方法返回的 的IAsyncResult属性轮询以确定命令是否已完成IsCompleted;或者使用AsyncWaitHandle返回IAsyncResult的 的 属性等待一个或多个命令完成。BeginExecuteNonQuery 如果使用ExecuteReader或BeginExecuteReader访问 XML 数据,SQL Serve...
();returncmd.ExecuteNonQuery(); } } }// Set the connection, command, and then execute the command and only return one value.publicstaticObjectExecuteScalar(String connectionString, String commandText, CommandType commandType,paramsSqlParameter[] parameters){using(SqlConnection conn =newSqlConnection(...
carriage return values for C#.net Case insensitive Replace cast from double to decimal Cast Interface to class Cast to Enum issue when value is null Casting an Int16 varible to Int in C# produces a runtime "Specified cast is not valid" exception casting from object to System.Reflection.Proper...
SqlCommand cmd = new SqlCommand("insert into mynews value ('插入一条新数据')", con); Command对象的构造函数的参数有两个,一个是需要执行的SQL语句,另一个是数据库连接对象。创建Command对象后,就可以执行SQL命令,执行后完成并关闭数据连接,示例代码如下所示。 cmd.ExecuteNonQuery(); //执行SQL命令 con....