'Spring Data: Unique field in MongoDB document

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; 

}

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.

Regards, Steffen

javaspringmongodbspring-data


Solution 1:[1]

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;

Solution 2:[2]

This worked for me, but you have to delete your database and then re-run your application

 spring.data.mongodb.auto-index-creation=true

Solution 3:[3]

First, use Indexed annotation above of your field in your model as shown below:

@Indexed(unique = true)
private String email;

Also, you should programmatically define your index. You should use the below code when defining your MongoTemplate.

mongoTemplate.indexOps("YOUR_COLLECTION_NAME").ensureIndex(new Index("YOUR_FEILD_OF_COLLECTION", Direction.ASC).unique());

For your case, you should use:

mongoTemplate.indexOps("users").ensureIndex(new Index("email", Direction.ASC).unique());

Solution 4:[4]

As of Spring Data MongoDB 3.0, automatic index creation is turned off by default. So basically, besides using @Indexed, you have to configure default indexing options. What you need to do is to make spring.data.mongodb.auto-index-creation=true in the application.properties file, and then @Indexed will work like a charm!

Solution 5:[5]

You can try one of the below solutions, it worked for me.

Note: Please delete your db before you re-try with the below solutions.

Solution - 1

@Indexed(unique = true, background = true)
private String emailId;

Solution - 2

Add spring.data.mongodb.auto-index-creation=true to your application.properties file.

or

Add spring.data.mongodb.auto-index-creation:true to your yaml file

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 V.Aggarwal
Solution 2 Mohamad Chamanmotlagh
Solution 3 Ahmad Vatani
Solution 4
Solution 5 Robin Xavier

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