Schema '1.json' required for migration was not found at the schema out folder
Tags: android, migration, androidroom, databasemigration
Published: 2023-08-12 02:19:13

If you are an Android developer, you may have come across the infamous "Schema '1.json' required for migration was not found at the schema out folder" error while working with Android Room, the SQLite object mapping library. This error can be quite frustrating, but fear not! In this article, we will explore the possible causes of this error and provide solutions to help you overcome it.

The "Schema '1.json' required for migration was not found at the schema out folder" error typically occurs when you are trying to run a migration in Android Room. Migrations are necessary when you make changes to your database schema, such as adding or removing tables or columns. Room uses a JSON file to keep track of the database schema versions, and this error indicates that the required JSON file is missing.

So, why is the JSON file missing? One possible cause is that you have not properly configured the Room database's migration strategy. Room requires you to provide a `Migration` object that defines how to migrate from one schema version to another. If you forget to add a migration for a specific version, Room will throw the "Schema '1.json' required for migration was not found at the schema out folder" error.

Another possible cause is that you have not properly placed the JSON file in the correct location. By default, Room expects the JSON file to be located in the "schema out" folder. Make sure that you have correctly set up the folder structure and that the JSON file is present in the expected location. Double-checking the file path can save you from this error and some unnecessary head-scratching!

Now, let's move on to the solutions! To fix the "Schema '1.json' required for migration was not found at the schema out folder" error, follow these steps:

1.  Ensure you have defined a proper migration strategy for your Room database. Make sure to include a migration for each schema version.
2.  Double-check the file path and location of the JSON file. Ensure it is present in the correct "schema out" folder.
3.  If you are using a custom location for the JSON file, make sure to update the Room database configuration accordingly.

By following these steps, you should be able to resolve the "Schema '1.json' required for migration was not found at the schema out folder" error. Remember, Room is a powerful library that simplifies database management in Android, but it requires careful configuration to avoid these types of errors.

In conclusion, the "Schema '1.json' required for migration was not found at the schema out folder" error in Android Room can be frustrating, but with the right approach, it can be easily fixed. Always ensure you have defined a proper migration strategy and double-check the file path and location of the JSON file. By doing so, you will be on your way to a smoothly running Room database in no time!

References:
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*   Android Room Documentation: [https://developer.android.com/training/data-storage/room](https://developer.android.com/training/data-storage/room)
*   Stack Overflow: [https://stackoverflow.com/questions/54718442/android-room-schema-json-required-for-migration-was-not-found-at-the-schema-o](https://stackoverflow.com/questions/54718442/android-room-schema-json-required-for-migration-was-not-found-at-the-schema-o)