Databases Intermediate

What is Index?

A data structure that improves the speed of data retrieval operations on database tables at the cost of additional storage.

Indexes work like a book index — they allow the database to find rows without scanning the entire table. Without an index, a query on a million-row table checks every row. With an index, it jumps directly to matching rows.

Types include B-tree (default, good for ranges), hash (exact matches), GIN (full-text search), and GiST (geometric data). Over-indexing slows down writes since indexes must be updated on every INSERT/UPDATE.

Related Terms

ORM (Object-Relational Mapping)

A technique that lets you interact with a database using object-oriented code instead of writing raw SQL queries.

A middleware server that sits between applications and databases, providing connection pooling, load balancing, and query routing.

A centralized repository optimized for analytical queries that integrates data from multiple operational sources.

MVCC (Multi-Version Concurrency Control)

A technique where the database maintains multiple versions of data to allow concurrent reads and writes without locking.

Query Optimization

The process of improving database query performance through indexing, query rewriting, and schema design techniques.

An open-source, in-memory data store used as a database, cache, message broker, and queue with sub-millisecond response times.

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