C#中的SQL更新语句 [英] SQL update statement in C#
本文介绍了C#中的SQL更新语句的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我有表学生
P_ID LastName FirstName Address City
1 Hansen Ola
2 Svendson Tove
3 Petterson Kari
4 Nilsen Johan
...and so on
如何在C#中更改编辑代码
How do i change edit code in C#
string firstName = "Ola";
string lastName ="Hansen";
string address = "ABC";
string city = "Salzburg";
string connectionString = System.Configuration.ConfigurationManager
.ConnectionStrings["LocalDB"].ConnectionString;
using (SqlConnection connection = new SqlConnection(connectionString))
using (SqlCommand command = connection.CreateCommand())
{
command.CommandText = "INSERT INTO Student (LastName, FirstName, Address, City)
VALUES (@ln, @fn, @add, @cit)";
command.Parameters.AddWithValue("@ln", lastName);
command.Parameters.AddWithValue("@fn", firstName);
command.Parameters.AddWithValue("@add", address);
command.Parameters.AddWithValue("@cit", city);
connection.Open();
command.ExecuteNonQuery();
connection.Close();
}
编辑其中 Lastname 字段具有姓氏值的条目并且名字字段具有名字值。
to edit entry where Lastname field has lastname value and FirstName field has firstname value.
我不想这样使用
UPDATE Persons SET Address='Nissestien 67', City='Sandnes'
WHERE LastName='Tjessem' AND FirstName='Jakob'
,然后我将原始语句编辑为
and i edited my original statement to
command.CommandText = "UPDATE Student(LastName, FirstName, Address, City)
VALUES (@ln, @fn, @add, @cit) WHERE LastName='" + lastName +
"' AND FirstName='" + firstName+"'";
但是该语句没有得到执行,为什么会抛出SQL异常?
but the statement is not getting executed, why is it throwing SQL exception ? Is there nay solution to it ?
推荐答案
这不是更新SQL中记录的正确方法:
This is not a correct method of updating record in SQL:
command.CommandText = "UPDATE Student(LastName, FirstName, Address, City) VALUES (@ln, @fn, @add, @cit) WHERE LastName='" + lastName + "' AND FirstName='" + firstName+"'";
您应该这样写:
command.CommandText = "UPDATE Student
SET Address = @add, City = @cit Where FirstName = @fn and LastName = @add";
然后,添加与插入操作相同的参数。
Then you add the parameters same as you added them for the insert operation.
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