C # codefirst (EF framework) Code first creates a database

Namespace Webef.model
{
public class Modelcontext:dbcontext//Inherit DbContext from EF framework
{

Public Modelcontext (): Base ("Name= profile Name") {//Read config file

/* Configuration file formatting

<connectionStrings>
<add name= "Profile Name"
connectionstring= "Data source= (., localhost, remote IP); Initial catalog= database name; User id=sql account; password= password; "
Providername= "System.Data.SqlClient"/>
</connectionStrings>

*/
}

A class is a table

Public dbset< class name (table name) > class (table) name {set;get;} Storing objects in Dbset memory
Public dbset< class name (table name) > class (table) name {set; get;}
Public dbset< class name (table name) > class (table) name {set; get;}

protected override void Onmodelcreating (Dbmodelbuilder modelBuilder)
{
Base. Onmodelcreating (ModelBuilder);

modelbuilder.entity< Class name (table name) > (). ToTable ("table name");//alias to database table

modelbuilder.entity< Class name (table name) > (). ToTable ("table name");

modelbuilder.entity< Class name (table name) > (). Haskey (p = new {p.studentno, P.courseno}). ToTable ("table name");//p set two primary keys for an SCC
}
}
}

Dbfrist refers to database precedence, which maps a database into a solid model.

Modelfrist refers to pattern precedence, which maps solid modules to databases.

Codefrist is the use of C # code to generate a database.

Call

Suppose you create a student table and a course table and you need to create a student class and course class as follows

Namespace WEBEF
{
public partial class WebForm1:System.Web.UI.Page
{
protected void Page_Load (object sender, EventArgs e)
{
using (var context = new Modelcontext ())
{

Context. Database.createifnotexists ();

var student = new Student ("10001", "John Doe", "male", "CS");//Instantiate Student Class (student table, add a student information)

var c = New course//Instantiate course class, (curriculum, add a course)

{
No=1,
Name= "C Language",
Preno=null,
Credit=3

};

Context. Student.add (Student);//Add a student information

Context. Course.add (c);//Add a course
Context. SaveChanges ();//Save changes to save the data to the database

Response.Write ("Operation succeeded! ");
}

}
}
}

Student class

Namespace Webef.model
{
public class Student
{

private string No;
private string name;
private string sex;
private short age;
private String Dept;

Public Student () {}
Public Student (string No., String name, String sex, Short age, String dept)
{
this.no = no;
THIS.name = name;
This.sex = sex;
This.age = age;
this.dept = Dept;
}
<summary>
[key] Set Primary key
No indicates the number of studies
</summary>
[Key]
public string No {get {return this.no;} set {this.no = value;}}

<summary>
Name
</summary>
public string Name {get {return this.name;} Set{this.name=value;}}

<summary>
Gender
</summary>
public string Sex {set {this.sex = value;} get {return Sex;}}

<summary>
Age
</summary>
Public short Age {set {this.age = value;} get {return-age;}}

<summary>
Your department
</summary>
public string Dept {set {this.dept = value;} get {return Dept;}}

[ForeignKey ("Studentno")]//setting foreign keys
Public virtual list<scc> SCCs {set; get;}

}
}

Course Category

Namespace Webef.model
{
public class Course
{

<summary>
Course Number
</summary>
[Key]
public int No {set; get;}

<summary>
Course Name
</summary>
public string Name {set; get;}

<summary>
First class number
</summary>
///

public int? Preno {set; get;} The number indicates that the value can be empty

<summary>
Course Xuef
</summary>
Public short credits {set; get;}

[ForeignKey ("Courseno")]//set the course number as the foreign key for the selected schedule
Get all Elective courses
Public virtual list<scc> SCCs {set; get;}

[ForeignKey ("Preno")]//set the first course as a foreign key

Get all the first lessons
Public virtual list<course> Courses {set; get;} Get all the first lessons

}
}

Choose a timetable (a multi-to-many relationship between the student and the curriculum for the student table and the table of the curriculum)

Namespace Webef.model
{
public class SCC
{
<summary>
School Number
</summary>
///

public string Studentno {set; get;}

<summary>
Elective number
</summary>
///

public int Courseno {set; get;}

<summary>
Scores
</summary>
public int Grade {set; get;}

}
}

C # codefirst (EF framework) Code first creates a database