[英]Updating Database Using Dapper
I don't know if is this is possible in dapper . 我不知道这在dapper中是否可行。 Let's say I have this class:
假设我有这个课程:
public class Student
{
public int Id{get;set;}
public string FirstName{get;set;}
public string LastName{get;set;}
public int UpdateStudent(Student student)
{
string sql="Update Student set FirstName=@FirstName, LastName=@LastName where Id=@Id";
Dapper.Execute(sql, student)
}
}
Now, on the calling code, I will have something like this: 现在,在调用代码上,我将得到以下内容:
Student student=new Student();
student.Id=1;
student.FirstName="abc";
student.UpdateStudent(student);
Now, if we are going to update the Student
and only provide Id
and FirstName
, it will throw an error that I will also need to provide the LastName
. 现在,如果我们要更新
Student
并仅提供Id
和FirstName
,它将抛出一个错误,我也需要提供LastName
。 I am looking for a solution that can be use that even if if I do not specify the Student.LastName
, it will still do the update and since I don't specify the LastName
, the Student.LastName
will remain the same. 我正在寻找一种可以使用的解决方案,即使我未指定
Student.LastName
,它仍然会进行更新,并且由于我未指定LastName
,所以Student.LastName
将保持不变。
Ok here is a quick and dirty: 好吧,这是一个快速而肮脏的:
I did not compile or test this so it might have a typo
我没有编译或测试它,所以可能有错字
public static void UpdateFromItem(string tableName, object updatevalues, object selectorvalue)
{
string updateStr=new String();
string whereStr=new String();
foreach (PropertyInfo prop in updatevalues.GetType().GetProperties())
{
if (prop.GetValue(parms, null) != null)
updateStr.AppendFormat(" %s=%s",prop.Name, prop.GetValue(parms, null));
}
foreach (PropertyInfo prop in selectorvalues.GetType().GetProperties())
{
if (prop.GetValue(parms, null) != null)
updateStr.AppendFormat(" %s=%s",prop.Name, prop.GetValue(parms, null));
}
string sqlStmt=string.Format(@"UPDATE %s SET %s WHERE %s",tableName, updateStr,wherreStr);
Drapper.Execute(sqlStmt);
}
Call it like this 这样称呼它
UpdateFromItem("Student", new { FirstName : "abc"}, new { Id : 1 });
I made a generic solution above, you could also "know" about the id field for student object specifically then a solution like this would work: 我在上面做了一个通用的解决方案,您还可以“了解”学生对象的id字段,然后这样的解决方案就可以了:
public static void UpdateStudent(Student inobj)
{
string updateStr=new String();
string whereStr=string.Format(@"Id=%s",inobj.Id);
foreach (PropertyInfo prop in inobj.GetType().GetProperties())
{
if ((prop.GetValue(parms, null) != null) && (prop.Name != 'Id'))
updateStr.AppendFormat(" %s=%s",prop.Name, prop.GetValue(parms, null));
}
string sqlStmt=string.Format(@"UPDATE %s SET %s WHERE %s",tableName, updateStr,wherreStr);
Drapper.Execute(sqlStmt);
}
People will point out that this is has injection risk. 人们会指出,这是有注射风险的。 That can be solved by composing a parameter list -- but I think you get the idea.
可以通过编写参数列表来解决,但是我想您知道了。 Basically you need a loop.
基本上,您需要一个循环。
This isn't hard you will need an if statement, something like this: 这并不难,您将需要一个if语句,如下所示:
if (student.lastName.IsNullOrEmpty())
Dapper.Execute("Update Student set FirstName=@FirstName where Id=@Id", student);
else
Dapper.Execute("Update Student set FirstName=@FirstName, LastName=@LastName where Id=@Id", student);
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