How to efficiently store List data in MySQL JSON columns using Spring Boot and Flyway?

Other Questions MySQL
1

I’m having trouble figuring out the best way to store List data in JSON columns with MySQL. I’m using Spring Boot and Flyway for my project.

Here’s what I’m trying to do:

  • Store albumIds and artistIds as Lists in JSON format
  • Use Flyway for database migrations
  • Avoid column duplication when the app restarts
  • Follow best practices for performance (like indexing)

The main issue I’m facing is that I keep getting a SQLSYNTAXERROREXCEPTION about duplicate columns every time I restart the app. I thought I had set up checks in my database initializer class using an entity mapper, but it’s not working as expected.

Can anyone help me figure out:

  1. The best way to model this in the entity class?
  2. How to handle Flyway migrations safely?
  3. How to stop these errors from happening on app restarts?

Thanks for any advice!

2

From my experience, using Jackson’s ObjectMapper for JSON serialization/deserialization works well with MySQL JSON columns. In your entity, annotate the List fields with @Column(columnDefinition = “json”) and @JsonSerialize(using = ListToJsonSerializer.class). Create custom serializer/deserializer classes to handle the conversion.

For Flyway, ensure your migration scripts use ALTER TABLE IF NOT EXISTS to prevent duplicate column errors. Set spring.flyway.baseline-on-migrate=true in application.properties to handle existing schema.

To avoid issues on restart, implement a custom JpaSystemException handler. This can catch and log any database-related exceptions without causing the application to fail.

Remember to create appropriate indexes on your JSON columns for better query performance. Use functional indexes if you need to query specific JSON properties frequently.

3

hey alexm, i’ve had similar headaches. try using @Type(type = “json”) annotation on ur List fields in the entity class. for flyway, make sure ur migration scripts use IF NOT EXISTS when creating columns. also, set spring.jpa.hibernate.ddl-auto=validate in application.properties to prevent auto schema updates. that should fix the restart issue. good luck!

4

I’ve tackled this issue before, and here’s what worked for me:

For storing Lists in JSON columns, use the @Type(type = “json”) annotation on your entity fields. This lets Hibernate handle the JSON conversion seamlessly.

To prevent duplicate column errors, make sure your Flyway migration scripts use IF NOT EXISTS clauses. Also, set spring.jpa.hibernate.ddl-auto=none in your application.properties. This stops Hibernate from trying to modify the schema on startup.

For better performance, create a composite index on the JSON columns using a generated column. Something like:

ALTER TABLE your_table ADD COLUMN album_ids_index VARCHAR(255) GENERATED ALWAYS AS (json_unquote(json_extract(album_ids, ‘$[0]’))) VIRTUAL;
CREATE INDEX idx_album_ids ON your_table(album_ids_index);

This approach lets you efficiently query the first element of your JSON arrays.

Lastly, consider using a custom JsonConverter if you need more control over the JSON serialization/deserialization process. This can help with any specific formatting requirements you might have.

5

yo alexm, been there done that. try @JsonSerialize and @JsonDeserialize on ur List fields. for flyway, use IF NOT EXISTS in ur scripts. set spring.jpa.hibernate.ddl-auto=none in app properties to stop auto updates. also, index those json columns for better performance. CREATE INDEX idx_album_ids ON ur_table ((CAST(album_ids AS JSON))) USING BTREE; good luck man!

6

I’ve dealt with similar issues in my projects. Here’s what worked for me:

For modeling the entity class, use a custom JSON converter. Create a separate class that extends AttributeConverter<List, String> and annotate your entity fields with @Convert(converter = YourCustomConverter.class).

Regarding Flyway migrations, I found it’s best to explicitly define the JSON columns in your migration scripts. Use the JSON data type and set a default value of an empty array (‘’). This prevents issues with null values.

To stop errors on app restarts, make sure your Flyway configuration has the ‘baseline-on-migrate’ property set to true. This tells Flyway to create a baseline if it hasn’t been run before.

Also, double-check your entity mapper. Ensure it’s not trying to recreate existing columns. You might need to add a check to see if the column already exists before attempting to create it.

Hope this helps! Let me know if you need more details on any part.