Entity Framework Code-First（9.10）：DataAnnotations - NotMapped Attribute

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DataAnnotations - NotMapped Attribute:

NotMapped attribute can be applied to properties of a class. Default Code-First convention creates a column for all the properties which includes getters and setters. NotMapped attribute overrides this default convention. You can apply NotMapped attribute to a property which you do NOT want to create a column in a database table for.

Consider the following example.

using System.ComponentModel.DataAnnotations;public class Student{    public Student()    {             }    public int StudentId { get; set; }         public string StudentName { get; set; }            [NotMapped]    public int Age { get; set; }}

 

As you can see in the above example, NotMapped attribute is applied to Age property of the Student class. So, Code First will not create a column to store Age information in the Student table as shown below.

Code-first also does not create a column for a property which does not have either getters or setters. Code-First will not create columns for FirstName and Age properties in the following example.

using System.ComponentModel.DataAnnotations;public class Student{    public Student()    {             }    private int _age = 0;    public int StudentId { get; set; }         public string StudentName { get; set; }        public string FirstName { get{ return StudentName;}  }    public string Age { set{ _age = value;}  }    }

 

Entity Framework Code-First（9.10）：DataAnnotations - NotMapped Attribute