How to build an EF environment? (Entity Framework), efentity

How to build an EF environment? (Entity Framework), efentity

1. What is EF?

EF is an Entity layer Framework encapsulated by. net for database interaction. Its full name is Entity Framework.

 

2. EF construction:

After the creation, we can see the content in it:

Let's take a look at what it has in it separately?

2. 1. After ef is created, we [open method-XML text editor] in EF to see what SSDL, CSDL, and MAPPING are the most important ones?

 

2.2.T4 Template

We call this thing the T4 template. Its function is to read the content in EF [. edmx] and generate class files one by one.

 

2.3.EF another important thing is the EF context object. [We call the add, delete, modify, and query method of the EF context object by instantiating it]

3. Use EF for a small logon example:

Create a web page: [some code]

1 <div> 2 <table> 3 <tr> 4 <td> User name: </td> 5 <td> 6 <asp: textBox ID = "txtLoginUserName" runat = "server"> </asp: TextBox> 7 </td> 8 </tr> 9 <tr> 10 <td> password: </td> 11 <td> 12 <asp: TextBox ID = "txtLoginPwd" runat = "server" TextMode = "Password"> </asp: textBox> 13 </td> 14 </tr> 15 <tr> 16 <td> 17 <asp: button ID = "BtnLogin" runat = "server" Text = "login" OnClick = "BtnLogin_Click"/> 18 </td> 19 <td> <a href = "javascript ;: "> forgot password </a> </td> 20 </tr> 21 </table> 22 </div>

1 protected void Page_Load (object sender, EventArgs e) 2 {3 4} 5 // instantiate an EF context object 6 sq_rEntities db = new sq_rEntities (); 7 protected void BtnLogin_Click (object sender, EventArgs e) 8 {9 string username = txtLoginUserName. text. trim (); 10 string pwd = txtLoginPwd. text. trim (); 11 // operate the UserInfor table through the entity object of EF, execute the lamada condition, 12 // db. set <UserInfor> (). where (u => u. userName = username & u. pwd = pwd) may be empty, Fi RstOrDefault gets the first 13 UserInfor user = db. set <UserInfor> (). where (u => u. userName = username & u. pwd = pwd ). firstOrDefault (); 14 // determines whether it is null. 15 if (user = null) 16 {17 Response. write ("incorrect user name or password! "); 18} 19 else20 {21 Response. Write (" Logon successful! "); 22} 23}

 

SQL statement Process Monitoring: EF without SQL injection:

Run-log on to the logon page