Spring Data:MongoDB文档中的唯一字段

问题描述

假设我有以下数据库实体:

let's say I have the following database entity:

@Document(collection = "users")
public class User {

    @Id
    private String id;

    private String firstname;

    private String lastname;

    private String email; 

}

如何强制字段电子邮件是唯一的?这意味着当应用程序尝试保存实体时，MongoDB 应该检查是否已经存在使用此电子邮件地址的用户记录.

How can I enforce the field email to be unique? That means MongoDB should check if a user record with this email address already exists when the application tries to save the entity.

问候，史蒂芬

推荐答案

MongoDB需要创建一个字段并建立索引，才能知道该字段是否唯一.

Mongodb needs to create and index a field in order to know whether the field is unique or not.

@Indexed(unique=true)
private String email;

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