How to create trigger in database

Muhammad Salman Rafique

Hi,

how to create trigger in database.

I have two table in database

1. Purchase

2. Stock

when any data add into Purchase table ,,,, it automatically add same data into Stock table

John Stegeman

You use the create trigger statement, which is documented quite well http://docs.oracle.com

Do you have a specific question about something you didn't understand from the docs?

Jagadekara

Use after insert trigger

Jagadekara

Oracle/PLSQL: AFTER INSERT Trigger

Hope this will help you

JohnWatson2

2875368 wrote:

Hi,
how to create trigger in database.
I have two table in database
1. Purchase
2. Stock
when any data add into Purchase table ,,,, it automatically add same data into Stock table

Why use a pl/sql trigger at all? A sql INSERT ALL statement will be faster, simpler, and more reliable.

--

John Watson

Oracle Certified Master DBA

John Stegeman

An excellent point, John. Triggers are much more often abused than used properly.

JohnWatson2

John Stegeman wrote:

An excellent point, John. Triggers are much more often abused than used properly.

I hate triggers! They mean that when I do something, without my knowledge something totally unrelated happens. Working in C, we would call this a "side effect". And programmers who write code with side effects should be shot  

John Stegeman

Well said, John Watson.

12cdb

>>I hate triggers! They mean that when I do something, without my knowledge something totally unrelated happens. Working in C, we would call this a "side effect". And programmers who write code with side effects should be shot  

Well it depends on the requirement right, otherwise every Oracle feature is meant to design to solve some puzzle.

More it depends on the correct usage. Anywhere used outside not designed for is bad!.

Pradeep

John Stegeman

The problem with triggers is:

• As John Watson says, they do mystical, magical, hidden things.
• They are often *intentionally* used to cause side effects, where the better approach is to do the thing you want in the first place. In other words, people use them as a shortcut to fixing their code.
• Most people DO NOT use triggers properly. They cause more problems, in aggregate, than they solve. When a beginning developer discovers triggers, they tend to get trigger-happy.

I would also not be unhappy if triggers were outlawed/removed from Oracle.

12cdb

I am not sure and I wouldn't imagine Oracle will ever remove it.

Think about system event triggers such as startup, logon etc..  which actually helps a lot.

Pradeep