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This article mainly introduces "how to use Code First mode in EF to add compound primary key to entity class". In daily operation, I believe many people have doubts about how to use Code First mode to add compound primary key to entity class in EF. The editor consulted all kinds of materials and sorted out simple and easy-to-use methods of operation. I hope it will be helpful to answer the doubt of "how to use Code First mode to add compound primary key to entity class in EF". Next, please follow the editor to study!

Using System;using System.Collections.Generic;using System.ComponentModel.DataAnnotations;using System.ComponentModel.DataAnnotations.Schema;using System.Linq;using System.Web;namespace MyFirstMvcApp.Models {/ login record / public class LoginRecordInfo {/ login email address (primary key) / / [Key,Column (Order=1)] public string Email {get; set } / the client IP / public string LoginHostIP {get; set;} / the client hostname of the login / public string LoginHostName {get; set } / logon time (primary key) / [Key,Column (Order=2)] public DateTime LoginTime {get; set;}

The compound primary key is set with the attributes Key and Column, where Key indicates that the field is the primary key, and Order is used to set the order of the primary key. Using Key and Column requires adding namespaces:

Namespace of Key: System.ComponentModel.DataAnnotations

Namespace of Column: System.ComponentModel.DataAnnotations.Schema

At this point, the study on "how to use the Code First pattern in EF to add compound primary keys to entity classes" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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