ASP EF Framework, Entity Framework (entityframework), Databasefirst

The DATABASEFIRST:EF framework automatically generates data layers and model based on the database.

Project--Add--New item--Data--ado.net Entity Data Model--build from database--New connection--Select server name, database--[Yes, include sensitive data in connection string]--Select datasheet, view in database, Stored procedure--complete--Overwrite web.config

Using System;
Using System.Collections.Generic;
Using System.Linq;
Using System.Web;
Using System.Web.UI;

Using System.Web.UI.WebControls; namespace WebApplication1 {public partial class WebForm1:System.Web.UI.Page {protected void Page_Load (  Object sender, EventArgs e) {}//Insert protected void Button1_Click (object sender,
            EventArgs e) {UserInfo UserInfo = new UserInfo ();
            Userinfo.email = "sss@256.com";
            Userinfo.regtime = DateTime.Now;
            Userinfo.username = "SSS56";
            Userinfo.userpass= "123456";  Effristmodelentities db = new effristmodelentities (); The class in the Model1.Context.cs. (Context class, which is an interaction with the database through this class) db.
            Userinfo.add (UserInfo);//Adds data to the EF and adds markup. Db.    SaveChanges (); The statement is executed before the data is saved to the database.
            Returns the number of rows affected.
        Response.Write (userinfo.id);
}//query protected void button2_click (object sender, EventArgs e) {            Effristmodelentities db = new effristmodelentities (); LINQ var userinfolist = from u in db.  UserInfo where u.id ==343 select U; A LINQ statement. U is a custom variable, where the type is userinfo type. The query is not executed in the database here.

            Returns a list collection. foreach (UserInfo UserInfo in userinfolist)//ef the deferred loading mechanism, where data is used to query the database.
            Do not query when not in use.
            {Response.Write (userinfo.username);
            }//select * from UserInfo where id=343//from UserInfo the execution order of the SQL statements in the database. where id=343//select *}//delete protected void Button3_Click (object sender, Ev
            
            Entargs e) {effristmodelentities db = new effristmodelentities (); /* The first way to delete var userinfolist = from u in db.
            UserInfo where u.id = = 345 Select U; UserInfo UserInfo=userinfolist.firstordefault (); Returns the first element, and if not, returns a default value of NULL if (UserInfo!= null) {//db. Userinfo.remove (UserInfo);
                Add a delete tag, but you must perform a query operation before you can successfully mark it. Db. Entry<userinfo> (UserInfo). state = System.Data.EntityState.Deleted;

                Add a delete tag, which can be marked directly without the need to execute the query. Db.  SaveChanges ();
            Performs a delete operation.
            } else {Response.Write ("The data to be deleted does not exist!!");
            }//The second deletion method.
            UserInfo UserInfo = new UserInfo () {id=344}; Db. Userinfo.remove (UserInfo);
            You must perform a query operation before marking (infrequently). Db. Entry<userinfo> (UserInfo).  state = System.Data.EntityState.Deleted;
            Add a delete tag, which can be marked directly without the need to execute the query. Db. SaveChanges (); If the data you want to delete does not exist, an error occurs.

        It is best to query before deleting. }//Modify protected void Button4_Click (object sender, EventArgs e) {Effristmodelentitie
            s db = new effristmodelentities (); var userinfolist = from u in db.
            UserInfo where u.id = = 343 Select U;
            var userInfo = Userinfolist.firstordefault ();
                if (userInfo!= null) {Userinfo.userpass = "666666"; Db. Entry<userinfo> (UserInfo).
                state = System.Data.EntityState.Modified; Db.
            SaveChanges ();
            } else {Response.Write ("The data to be modified does not exist!!"); }
        }
    }
}