Databases Intermediate

What is Trigger?

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

Triggers run automatically in response to data changes. They can execute BEFORE or AFTER the triggering event, and operate on each row or once per statement. Common uses include audit logging, data validation, maintaining derived data, and enforcing complex business rules.

In PostgreSQL, triggers call trigger functions written in PL/pgSQL. While powerful, overuse of triggers can make database behavior hard to debug and predict. Consider application-level logic for complex business rules.

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.

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

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

Time-Series Database

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

Prepared Statement

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

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

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