EF code-first CRUD operation

Many tutorials on the Internet are tied to mvc3. If mvc3 is left blank, how can we use it?

Create a console applicationProgramWe name it efcodefirst-books.

Step 2: add an entityframework reference.

Don't say that you are not using nuget again. If not, ask du Niang. Enter install-package entityframework in the nuget console. nuget will reference the latest EF version. The current version is 4.3.

Step 3: add an object class.

I created a new models folder and added the book class to it. The class definition is as follows:

 Using  System;  Using  System. Collections. Generic;  Using  System. LINQ;  Using  System. Web;  Namespace Efcodefirst_books.models {  Public   Class  Book {  Public   Int Bookid { Get ; Set  ;}  Public   String Bookname { Get ; Set  ;}  Public  String Author { Get ; Set  ;}  Public   String Publisher { Get ; Set  ;}  Public   Decimal Price { Get ; Set  ;}  Public  String Remark { Get ; Set  ;}}} 

Because it is a test, I added only one class.

Step 4: add the dbcontext class.

UsingSystem;UsingSystem. Collections. Generic;UsingSystem. LINQ;UsingSystem. Web;UsingSystem. Data. entity;NamespaceEfcodefirst_books.models {Public ClassAppdbcontext: dbcontext {PublicDbset <book> books {Get;Set;}}}
 

Step 5: check your database connection

If sqlexpress is installed, EF automatically points the connection to sqlexpress, and you do not need to modify it here.

If you want to change to another location, you need to modify the database connection:

   <  Entityframework  >      <  Defaultconnectionfactory  Type  = "System. Data. entity. Infrastructure. sqlconnectionfactory, entityframework"  >        <  Parameters  >          <  Parameter Value  = "Data Source =.; initial catalog = efcodefirst_books; Integrated Security = true"   />        </  Parameters  >      </  Defaultconnectionfactory  >    </  Entityframework  > 

Here I am pointing to the local database, using integrated security verification.

Step 6: Start crud operations

 Using  System; Using  System. Collections. Generic;  Using  System. LINQ;  Using  System. text;  Using  Efcodefirst_books.models;  Namespace  Efcodefirst_books {  Class  Program {  Static   Void Main ( String [] ARGs) {book = New  Book () {bookname = "  C # Advanced Programming  "  , Price = 151.8 m  , Publisher = "  Tsinghua University Press  "  , Author = " Wrox  "  ,}; Appdbcontext dbcontext = New  Appdbcontext (); dbcontext. Books. Add (book); dbcontext. savechanges ();  VaR Booksquery = From B In Dbcontext. Books Select  B; List <Book> bookslist = Booksquery. tolist (); book = Bookslist [0  ]; Book. Price = 203 m; dbcontext. savechanges (); dbcontext. Books. Remove (book );}}}