Difference between Cursor and Trigger in PLSQL

Oracle permits the definition of procedures that are automatically executed when an INSERT, UPDATE or DELETE statement is issued against the associated table. Database triggers refer to these procedures.

Triggers resemble stored procedures. A trigger can execute SQL and PL/SQL statements as a unit and invoke stored procedures. However, procedures and triggers are activated in different ways. A cursor is a Database object that retrieves rows from the database row-by-row, but it is primarily used to reduce network traffic. In addition to traversing records in a database, cursors facilitate data retrieval, addition and deletion of records. This article will examine the distinctions between the cursor and the trigger.

What is the Cursor in PL/SQL?

A cursor is just a pointer to the current context region. Context area is a memory region produced by Oracle during the processing of a SQL query. Therefore, the cursor is responsible for retaining the rows returned by a SQL query. PL/SQL manages the context region with the aid of the cursor. The active set is essentially the set of rows held by the cursor. There are two kinds of cursors: implicit cursor and explicit cursor.

Advantages:

• They are useful for processing each row individually and validating each row individually.
• Utilizing cursors allows for enhanced concurrent control.
• While loops execute more slowly than cursors.

Features:

• A cursor keeps track of the current position in the result set. It enables you to perform multiple operations row by row against a result set, either with or without returning to the original table.

Disadvantages:

• They use additional resources each time, which may result in a network round trip.
• An increase in the number of network round trips can degrade performance and slow down the network.

What is the Trigger in SQL?

A Trigger is a program automatically performed in reaction to certain events, such as database changes. DDL and DML statements, as well as any Database activity, are a few of the events for their execution. Thus, triggers are saved in the database and activated when certain circumstances are met. Consequently, they may be defined for any schema, table, view, etc. BEFORE INSERT, AFTER INSERT, BEFORE UPDATE, AFTER UPDATE, BEFORE DELETE, and AFTER DELETE are the six kinds of triggers.

Features:

• Event Type - It must be declared to process the UPDATE event.
• Object Scope- It must be declared to handle the UPDATE event only on the user password table.
• Statement Body - It must have a statement body to determine whether or not the password has actually been changed.

Advantages:

• They aid in monitoring all database modifications.
• Additionally, they aid in upholding the integrity limitations.

Disadvantages:

• They are very difficult to see, making debugging tough.
• Using triggers excessively or implementing complicated code inside a trigger might hinder performance.

Cursor vs. Trigger

Conclusion

This comparative analysis between cursor and trigger has reached its conclusion. I hope you like this guide. We began with a quick difference between cursor and trigger. We also examined the benefits, drawbacks, and characteristics of cursor vs. trigger. Finally, we've contrasted the difference between cursor and trigger.

If you experience any difficulty following along, please let me know in the comment box. Happy learning!

Related Questions

1. How many rows can a cursor accommodate?

A cursor is a pointer to a specific row inside a group of rows. The cursor can only reference one row at a time, but it may navigate to additional rows as required.

2. What are the four different sorts of cursors?

Different Types of Cursors in SQL Server:

• Static Pointers
• Adaptive Cursors
• Only Forward Cursors
• Keyset Driven Cursors