PostgreSQL
PostgreSQL β advanced features, JSONB, extensions, performance tuning, and .NET integration
MS SQL Server
Microsoft SQL Server β T-SQL, execution plans, indexing strategies, and performance optimization
MongoDB
MongoDB β document model, aggregation pipeline, indexing strategies, and schema design patterns
Redis
Redis β data structures, caching patterns, pub/sub, and distributed locking strategies
Elasticsearch
Elasticsearch β indexing, full-text search queries, mapping, cluster management, and .NET clients