Trigger

What is a Trigger?

A trigger also known as a trigger, it is a kind of script in SQL, MySQL or PostgreSQL programming language for databases.

It is a series of procedures that are executed, according to defined instructions, when certain operations are carried out, on the information contained in a database.

Generally, a trigger it is triggered when actions are executed to insert, remove or modify the data of a table.

What is a trigger for

The triggers or triggers, they serve to better manage the database automatically, without a person having to intervene.

They are generally used for guarantee the integrity of the information, through restrictions, requirements or verification actions, to avoid errors and facilitate the synchronization of information.

All this within the same database, without resorting to external programming languages.

A trigger is built under the following structure:

• Activation call or trigger of the code to be executed.
• Restriction or condition that is required to perform the action, which can be a condition or a nullity.
• Execution action, which corresponds to the execution instructions after checking the conditions or restrictions.

Trigger Examples

To illustrate how a trigger can be used, imagine that you need to duplicate a separate table from the information that is inserted into another.

If you program a trigger to be executed every time an Insert is performed on the first table, the same operation will also be performed on the second table automatically.

Therefore, it is convenient to bear in mind that this trigger has a large number of uses that can facilitate programming work.

A trigger can be programmed, for example, to:

• Maintain an updated copy of customers who enter an online store.
• Place an order for a product, when the stock in the warehouse reaches a certain quantity.
• Keep a record of the actions done by each user on a database.
• Automatically generate calculations on one or more columns.
• Avoid invalid data entry or illegal transactions.
• Conduct audits on user activities.
• Synchronize tables that duplicate information.
• Keep statistics on access to the database.
• View certain events or generate alerts when certain actions are generated in the database.

It also serves to carry out trigger marketing and trigger email activities. It consists of triggering notifications or personalized messages, to reach the potential customer with greater differentiation. For example, birthday messages or, on special occasions, remember invitations to face-to-face or online events.

More about Trigger

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