using LINQ from Database to List in c#

Question

i have a t_my_class table structure like below (MySql table)

id     class     group     age     name     surname
1      9         A         18      sarah    brown
2      10        B         20      joe      sanders
3      8         A         17      elisa    connor
4      10        C         23      sandra   brown

and i have a struct and a list of that struct

struct MyClass
{
   int id;
   string class;
   string group;
   int age;
   string name;
   string surname;
}
List<MyClass> Students = new List<MyClass>();

Now, can u tell me which LINQ query to use to select all data from t_my_class table to Students List.

Marc Gravell · Accepted Answer · 2011-10-20 07:23:31Z

5

Firstly, that should almost certainly not be a struct - it should be a class. Now, you have a couple of choices; if you do already have a LINQ-enabled ORM hooked up, then it should be simply:

var students = myContext.Students.ToList();

If you aren't already using an ORM tool then a micro-ORM might help, for example dapper-dot-net works with MySql AFAIK, allowing:

var students = connection.Query<Student>("select * from t_my_class").ToList();

With:

class Student
{
   public int Id {get;set;}
   public string Class {get;set;}
   public string Group {get;set;}
   public int Age {get;set;}
   public string Name {get;set;}
   public string Surname {get;set;}
}

answered Oct 20, 2011 at 7:23

Marc Gravell

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2 Comments

christofr Over a year ago

Can you please elaborate on why we shouldnt use a Struct? (purely interested).

Marc Gravell Over a year ago

@christofr structs are very rare, and unless you know exactly why you are using a struct, a class should be assumed. In particular, structs make poor choices for "object"-type data (and a student is an object, rather than a value). Specific reasons: it is over-sized for a struct, would probably be incorrectly mutable, and the copy-semantics usually cause huge headaches.

Pranay Rana · Accepted Answer · 2011-10-20 07:22:38Z

1

var students = from std in Students
               select std.

enter image description here

More : Learn SQL to LINQ (Visual Representation)

answered Oct 20, 2011 at 7:22

Pranay Rana

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Comments

Sai Kalyan Kumar Akshinthala · Accepted Answer · 2011-10-20 07:22:32Z

0

var students = from p in entities.t_my_class 
select p;

answered Oct 20, 2011 at 7:22

Sai Kalyan Kumar Akshinthala

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