7 articles
RSSHow to fix Mongoose errors — useNewUrlParser removed, strictQuery default flip, populate returning null, lean() losing methods, discriminator setup, transaction sessions, and TypeScript Document types.
How to fix MongoDB aggregation pipeline issues — $lookup field matching, $unwind on missing fields, $match placement, $group _id, type mismatches, and pipeline debugging.
How to fix MongoDB schema validation errors — $jsonSchema rules, required fields, type mismatches, enum constraints, bypassing validation for migrations, and Mongoose schema conflicts.
How to fix MongoDB 'not primary' errors when writing to a replica set — read preference misconfiguration, connecting to a secondary, replica set elections, and write concern settings.
How to fix Mongoose ValidationError when saving documents — required field errors, type cast failures, custom validator errors, and how to handle validation in Express APIs properly.
How to fix the MongoDB E11000 duplicate key error by identifying duplicate fields, fixing index conflicts, using upserts, handling null values, and resolving race conditions.
How to fix MongoDB 'MongoServerError: bad auth Authentication failed', 'MongoNetworkError: connect ECONNREFUSED 127.0.0.1:27017', and 'MongooseServerSelectionError' connection errors. Covers MongoDB not running, connection string format, Atlas network access, Docker networking, authentication, DNS/SRV issues, TLS/SSL, and Mongoose options.