Both stored procedures and triggers are very important knowledge in the database. Next, we will compare the differences between the two in many aspects in the article, which has a certain reference value and hopes to be helpful to everyone.
What is a trigger?
A trigger is a process (code segment) that is automatically executed when certain events occur on a table/view in the database. Triggers are mainly used to maintain integrity in the database. Triggers are also used to enforce business rules, audit changes in the database, and replicate data. The most common triggers are Data Manipulation Language (DML) triggers that fire when data is manipulated. Some database systems support non-data triggers, which fire when data definition language (DDL) events occur. These triggers can be used especially for auditing. The Oracle database system supports schema-level triggers.
What are stored procedures?
Stored procedures are applications that can access relational databases. Typically, stored procedures are used to validate data and control access to the database. If some data processing operations require the execution of multiple SQL statements, such operations are implemented as stored procedures. When calling a stored procedure, you must use the CALL or EXECUTE statement. Stored procedures can return results (such as the results of a SELECT statement). These results can be used by other stored procedures or applications. Languages used to write stored procedures usually support control structures such as if, while, for, etc. Depending on the database system used, stored procedures can be implemented in a variety of languages.
The difference between stored procedures and triggers:
(1) A stored procedure is a set of SQL statements that have been created and stored in the database. So we can reuse code over and over again. A trigger is a special stored procedure that is not directly invoked by the user. When creating a trigger, it is defined to be triggered when a specific type of data modification is performed on a specific table or column.
(2) The user can use the Execute or Exec statement to directly call or execute the stored procedure, but cannot directly call or execute the trigger. Triggers are only automatically executed when the associated event fires.
(3) Stored procedures can take input parameters while triggers cannot take parameters as input We cannot pass parameters as input to a trigger.
(4) Stored procedures can return zero or n values, and triggers cannot return values.
(5) We can use transactions in stored procedures, and transaction processing is not allowed within triggers.
(6) Stored procedures are usually used to perform user-specified tasks, and triggers are usually used for audit work.