Simple use of linq to SQL

1. Create a winform project.

2. Add a Linq to SQL class named Northwind

3. Open the server resource manager and drag the table to the linq to SQL class. The entity class is generated by.

4. instantiate the DataContext class

NorthwindDataContext dc = new NorthwindDataContext();

5. Now you can use Linq to SQL.

A. query all Employees data

Var ee =
From employee in dc. Employees
Select employee;

B. Add a Where condition to query all cities = London in the Employee table.

             e2 =                 employee  employee.City ==                  employee;

 

C. query the data of EmployeeID <5

             e3 =                 employee  employee.EmployeeID <                  employee;

 

D. query the employees whose employment date is before January 1, January 1, 1993.

             e4 =                 employee  employee.HireDate <  DateTime(, ,  employee;

 

E. Multiple query Conditions

             e5 =                 employee  employee.HireDate <  DateTime(, ,  employee.EmployeeID <                  employee;

 

F. like statement

 e6 =                 employee  SqlMethods.Like(employee.FirstName,                  employee;

 

G. query the specified Column

 e7 = employee                   ===

 

H. subquery

             e8 =                 employee  employee.Orders.Count >                  employee;

 

I. Internal Connection

             e9 =                 cus  cus.City ==                  ord;

 

J. Add

            Employees m = = = = 

 

K. Modify

             e10 = dc.Employees.FirstOrDefault(employee => employee.LastName == = 

 

L. Delete

             e10 = dc.Employees.FirstOrDefault(employee => employee.LastName == 

 

The exercise code uses Vs2012 and the Microsoft northwnd sample database.

Code download: http://pan.baidu.com/s/1pJyh0Mn