Quick Answer: What Is PL SQL Trigger?

What is trigger and its types?

Triggers are database object.

Basically, these are a special type of stored procedure that is automatically fired/executed when a DDL or DML command statement related to the trigger is executed.

Triggers are used to assess/evaluate data before or after data modification using DDL and DML statements..

How do you write a trigger?

Creating TriggersCREATE [OR REPLACE] TRIGGER trigger_name − Creates or replaces an existing trigger with the trigger_name.{BEFORE | AFTER | INSTEAD OF} − This specifies when the trigger will be executed. … {INSERT [OR] | UPDATE [OR] | DELETE} − This specifies the DML operation.More items…

Who uses PL SQL?

The companies using PL/SQL are most often found in United States and in the Computer Software industry. PL/SQL is most often used by companies with 50-200 employees and 1M-10M dollars in revenue.

Is PL SQL only for Oracle?

PL/SQL only can execute in an Oracle Database. It was not designed to use as a standalone language like Java, C#, and C++. In other words, you cannot develop a PL/SQL program that runs on a system that does not have an Oracle Database. PL/SQL is a high-performance and highly integrated database language.

What are advantages and disadvantages of PL SQL?

The main disadvantages of PL/SQL is its lack of portability….Advantages of PL/SQLsupport for SQL,closer integration with Oracle leading to better performance, and.support for object-oriented programming.

What is trigger in PL SQL with examples?

Trigger is invoked by Oracle engine automatically whenever a specified event occurs. Trigger is stored into database and invoked repeatedly, when specific condition match. A database manipulation (DML) statement (DELETE, INSERT, or UPDATE). … A database definition (DDL) statement (CREATE, ALTER, or DROP).

What is the use of trigger block in PL SQL statement?

Traditionally, triggers supported the execution of a PL/SQL block when an INSERT , UPDATE , or DELETE occurred on a table or view. Starting with Oracle8i, triggers support system and other data events on DATABASE and SCHEMA . Oracle Database also supports the execution of a PL/SQL or Java procedure.

What are the types of triggers in PL SQL?

Types of Triggers in OracleDML Trigger: It fires when the DML event is specified (INSERT/UPDATE/DELETE)DDL Trigger: It fires when the DDL event is specified (CREATE/ALTER)DATABASE Trigger: It fires when the database event is specified (LOGON/LOGOFF/STARTUP/SHUTDOWN)

What is trigger cursor functions in PL SQL?

The main function of the cursor is retrieval of rows from the result set one at a time (row by row). The main function of trigger is to maintain the integrity of the database. 5. A cursor is activated and thus created in response to any SQL statement.

What is trigger with example?

Trigger: A trigger is a stored procedure in database which automatically invokes whenever a special event in the database occurs. For example, a trigger can be invoked when a row is inserted into a specified table or when certain table columns are being updated.

Why we use PL SQL?

PL/SQL gives high productivity to programmers as it can query, transform, and update data in a database. PL/SQL saves time on design and debugging by strong features, such as exception handling, encapsulation, data hiding, and object-oriented data types. Applications written in PL/SQL are fully portable.

Why use triggers in SQL?

Triggers help the database designer ensure certain actions, such as maintaining an audit file, are completed regardless of which program or user makes changes to the data. The programs are called triggers since an event, such as adding a record to a table, fires their execution.

What is the function in PL SQL?

A called function performs the defined task and when its return statement is executed or when the last end statement is reached, it returns the program control back to the main program. Total no. of Customers: 6 PL/SQL procedure successfully completed.

What is trigger explain?

A trigger is a block of code that is executed automatically from a database statement. Triggers is generally executed for DML statements such as INSERT, UPDATE or DELETE. It resides in a database code and is fired automatically when the database code requires to perform the INSERT ,UPDATE or DELETE statement.

What is trigger and why it is used?

Triggers are used to maintain the referential integrity of data by changing the data in a systematic fashion. Each trigger is attached to a single, specified table in the database. Triggers can be viewed as similar to stored procedures in that both consist of procedural logic that is stored at the database level.