What are the Most Common Triggers?

ByAkshay Sharma

You may have heard about the DBMS, even if you are a beginner in programming. Database management systems are part and parcel of computer science. 

It helps us manage and organize data and allows for a more efficient and structured way to access it. 

This software allows for manipulation of the data, like deleting and editing. One of the most essential elements of database management systems is triggers.

Triggers in database management systems are responsible for automating specific actions when a predetermined condition or process is fulfilled. These triggers are of utmost importance in protecting the integrity of data and managing workflow.

In this blog, we will delve into the concept and utility of triggers. We will also learn about the most common triggers and how they fit into DBMS.

Additionally, we will learn about the triggers in SQL and MySQL compilers online. But before we do that, we must know what SQL and MySQL are.

So, without any further ado, let us get started.

What are Triggers?

Triggers are a set of specific events that are set to occur when certain pre-determined conditions are met. These can be understood as automated responses to events. 

These events can range from adding new data to deleting pre-existing data. Triggers help you, the programmer, to maintain data integrity and allow you to execute specific tasks without manual involvement, thus minimizing the risk of errors.

We can understand this better with an example:

Consider an online shopping application. The trigger that can be used in the application can be used to automatically send a request to stock up on an item as soon as the quantity goes below a certain threshold. 

When this threshold is reached, it triggers the request for stocking up (event). 

What are the most common triggers?

These are the most common triggers:

  • Audit Trail Triggers: This trigger tracks changes to essential data for auditing purposes.
  • Cascading Triggers: This allows users to maintain relationships between related tables.
  • Validation Triggers: It is used to enforce rules of business rules and data checks.
  • Logging Triggers: This trigger automatically records actions or specific events to be analysed for debugging.
  • Data Replication Triggers: This trigger synchronizes information across multiple servers or databases.
  • Archiving Triggers: The purpose of this trigger is to remove data from one table and insert it into another table to be able to keep historical records.
  • Notification Triggers: This trigger is most useful in time-sensitive cases. This sends notifications to the user based on predetermined conditions. 
  • Auto-Increment Triggers: This allows for generating unique identifiers to new records automatically.
  • Data Transformation Triggers: This trigger allows for modifying information before any insertion or update.
  • Backup Triggers: This trigger is proper for automatically creating information backups after predetermined events or times.

Now that we are familiar with the concept of triggers and the most common triggers, let us move on to what SQL is and the triggers in SQL.

What is SQL?

Structured query language (SQL) is an excellent tool in DBMS. It is a language used to store and process data in a relational database (it is a structured collection of data organized in tables and managed with rows and columns, and it represents relationships between the values of the stored data).

SQL statements can be used in various processes like storing, searching, and updating information from the database. It also helps in the optimal performance of the database.

Triggers in SQL

Trigger in SQL is an object from the database that contains the SQL code and is executed automatically when a particular predetermined event happens. Simply put, a specific event is the cause of this trigger in SQL.

Types of Triggers in SQL

SQL has two types of triggers in SQL. We will elaborate on each of them:

Row-Level Triggers

A row-level trigger is a type of trigger that automatically allows the event to occur in rows that are affected by UPDATE, INSERT, or DELETE statements.

These types of triggers are utilized very often to maintain databases’ integrity and enforce business rules. Row-level triggers, however, are very intensive and significantly impact database performance. So it is advised only to use them when necessary.

Let us take an example.

Suppose you allot a row-level trigger on a “client” table. In that case, it will automatically be triggered for each client record when you update, insert or delete data in that particular table.

Statement-Level Triggers

Unlike the row-level trigger, the statement-level trigger is executed only once for the duration of the triggering event. In simple words, the statement level trigger is activated once an SQL statement is processed, no matter the number of rows that are affected by it. It doesn’t allow processing every row individually but as a single action for each processed statement.

Let us take an example:

Suppose a statement-level trigger is assigned to a “purchase” table and a single SQL statement is executed to update numerous purchases. In that case, the trigger will be activated once for that statement, regardless of how many orders were modified.

Let us move to the next part of this blog i.e. what MySQL is and MySQL compiler online.

What is MySQL?

MySQL is a type of relational database management system (RDBMS) that is open-source. Open source means that the code to that software is accessible to the general public. MySQL is used in anything from personal projects to company-wide solutions.

This is one of the most popular DBMS software due to its versatility, ease of use, and reliability. MySQL is a pioneer in scalability and handling massive loads of information without any loss in performance.

Furthermore, MySQL’s active community and numerous web resources offer plenty of assistance to new and veteran users.

What is a MySQL compiler online?

MySQL compilers online are cutting-edge tools that make writing, developing, testing, and debugging SQL queries easier. This allows for executing MySQL queries on the browser without installing any application.

After you have written the code in MySQL compiler online, you can execute the process and see the results on the web. Some compilers are advanced and allow several features, such as query history and sharing and saving of these queries.

Conclusion

Triggers are a vital part of DBMS  and are essential in SQL and MySQL compiler online environments. The most common trigger types, such as audit trail and validation triggers, serve various functions to ensure that the data stays intact and that manual involvement is minimized. 

Additionally, types of triggers in SQL include row-level triggers and statement-level triggers.