Database trigger

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Database trigger

A database trigger is a procedural code that is automatically executed in response to certain events on a particular table or view in a database. Triggers are used to maintain the integrity of the information on the database, enforce business rules, and automate system tasks.

Types of Triggers[edit | edit source]

Database triggers can be classified into several types based on the event that initiates them:

Triggers can also be categorized based on their timing:

Components of a Trigger[edit | edit source]

A database trigger typically consists of the following components:

  • Triggering event: The event that causes the trigger to fire (e.g., INSERT, UPDATE, DELETE).
  • Triggering table or view: The table or view on which the trigger is defined.
  • Triggering condition: An optional condition that must be met for the trigger to execute.
  • Trigger action: The procedural code that is executed when the trigger fires.

Uses of Triggers[edit | edit source]

Triggers are used for various purposes, including:

  • Enforcing referential integrity: Ensuring that relationships between tables remain consistent.
  • Auditing changes: Keeping track of changes made to data in the database.
  • Synchronizing tables: Automatically updating related tables when changes occur.
  • Enforcing business rules: Ensuring that data modifications adhere to specific business rules.

Advantages and Disadvantages[edit | edit source]

Advantages[edit | edit source]

  • Automation of repetitive tasks.
  • Enforcement of complex business rules.
  • Improved data integrity and consistency.

Disadvantages[edit | edit source]

  • Can introduce complexity and make debugging difficult.
  • May impact performance if not designed properly.
  • Can lead to unintended consequences if not carefully managed.

Related Pages[edit | edit source]

See Also[edit | edit source]

Contributors: Prab R. Tumpati, MD