IT Glossary & Dictionary

A set of four properties (Atomicity, Consistency, Isolation, Durability) that guarantee reliable database transactions.

The default index type in most databases that organizes data in a balanced tree structure for efficient searching, sorting, and range queries.

A cache of database connections that can be reused, avoiding the overhead of creating new connections for each request.

A formatted string containing all parameters needed to establish a connection to a database server.

A query that transforms rows into columns, creating a pivot table view of aggregated data.

A temporary named result set defined within a SQL statement using the WITH clause, improving query readability and enabling recursion.

A database object that enables row-by-row processing of query results, useful for operations that cannot be done in bulk.

The process of creating copies of database data to protect against data loss from failures, corruption, or human error.

A technique that maintains a cache of database connections for reuse, reducing the overhead of creating new connections.

Rules enforced by the database to maintain data integrity, including NOT NULL, UNIQUE, CHECK, PRIMARY KEY, and FOREIGN KEY.

Different index structures (B-tree, Hash, GIN, GiST, BRIN) optimized for various query patterns and data types.

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

A horizontal scaling strategy that distributes data across multiple database servers based on a partition key.

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

A situation where two or more transactions permanently block each other by each holding locks that the other needs.

A distributed search and analytics engine built on Apache Lucene, optimized for full-text search and log analysis.

A data pipeline process that extracts data from sources, transforms it into a suitable format, and loads it into a destination system.

A PostgreSQL command that shows the execution plan of a query along with actual runtime statistics for performance tuning.

A database command that shows how the query planner will execute a SQL query, revealing join methods, scan types, and estimated costs.

A column that creates a link between two tables by referencing the primary key of another table.

A technique for searching natural language text in databases using word stemming, ranking, and relevance scoring.

A database that uses graph structures with nodes, edges, and properties to store and query highly connected data.

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

An SQL operation that combines rows from two or more tables based on a related column between them.

PostgreSQL's binary JSON data type that stores JSON documents with indexing, querying, and manipulation capabilities.

A database object that stores the precomputed result of a query, offering faster reads at the cost of periodic refresh.

A version-controlled change to a database schema that can be applied and reversed systematically.

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

The process of organizing database tables to reduce data redundancy and improve data integrity.

A category of databases that store data in non-tabular formats, optimized for specific data models and access patterns.

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

A technique of dividing large database tables into smaller, more manageable segments while maintaining a single logical table.

An advanced open-source relational database known for its reliability, feature richness, and standards compliance.

A pre-compiled SQL template that uses parameters instead of literal values, preventing SQL injection and improving performance.

A column or set of columns that uniquely identifies each row in a database table.

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.

The process of copying and maintaining database data across multiple servers for redundancy, failover, and read scaling.

A database feature that restricts which rows a user can access in a table based on security policies.

The structure definition of a database including tables, columns, data types, relationships, indexes, and constraints.

A pattern where records are marked as deleted with a flag or timestamp rather than being physically removed from the database.

Structured Query Language — the standard language for managing and querying data in relational databases.

A precompiled collection of SQL statements stored in the database that can be executed as a single unit.

A database optimized for storing and querying timestamped data points like metrics, sensor readings, and event logs.

A sequence of database operations that are treated as a single unit — either all succeed or all are rolled back.

A database object that automatically executes a specified function when certain events (INSERT, UPDATE, DELETE) occur on a table.

A database operation that inserts a new row if it does not exist, or updates the existing row if it does.

A PostgreSQL maintenance operation that reclaims storage from dead tuples and updates statistics for the query planner.