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!!"); }
}
}
}