Morphia/MongoDB retrieves query with identical elements

Question

im working on a social media backend in java. I decide to work with MongoDB and morphia for the contant management. Everytime i open up a query for finding documents it finds the right amount of documents but the query is full of the identical document. Can anybody help?

Ive searched everywhere for a solution but this seems like its not very popular

Answer 1

If your MongoDB query is returning the correct number of documents, but they are all identical, it could be due to a couple of reasons:

1. Query criteria: Ensure that your query criteria are correctly specified to retrieve the desired documents. If your query is too broad or missing specific conditions, it might return multiple identical documents that match the criteria. Double-check your query filters and make sure they are correctly defined.

2. Mapping configuration: Verify that your mapping configuration with Morphia is accurate. Morphia is an Object Document Mapping (ODM) library for MongoDB, and it helps map Java objects to MongoDB documents. Ensure that your entity classes are properly annotated with the correct annotations and that the mapping is correctly configured. In particular, pay attention to any field or property that might be causing duplicate values across documents.

3. Data integrity: Check the data in your MongoDB collection to ensure that it doesn't contain duplicate documents with the same values. It's possible that the issue is not related to the query or mapping but rather to the data itself. Review your data insertion process and ensure that you're not unintentionally inserting duplicate documents.

4. Unique indexes: Consider adding unique indexes to relevant fields in your MongoDB collection. Unique indexes enforce uniqueness for a particular field or combination of fields, preventing duplicate values from being inserted. By adding unique indexes, you can ensure that duplicate documents with the same values are not stored in your collection.

By investigating these aspects, you should be able to identify and address the issue of receiving identical documents in your MongoDB query results.