Contents
When to use trigger in insertor deletetriggering statement?
If a triggering statement includes a column list, the trigger is fired only when one of the specified columns is updated. If a triggering statement omits a column list, the trigger is fired when any column of the associated table is updated. A column list cannot be specified for INSERTor DELETEtriggering statements.
Do you need a unique name for a trigger?
Trigger names do not need to be unique with respect to other schema objects, such as tables, views, and procedures. For example, a table and a trigger can have the same name (however, to avoid confusion, this is not recommended). When Is the Trigger Fired?
What are the arguments to the trigger function?
Data type integer; the number of arguments given to the trigger function in the CREATE TRIGGER statement. Data type array of text; the arguments from the CREATE TRIGGER statement. The index counts from 0. Invalid indexes (less than 0 or greater than or equal to tg_nargs) result in a null value.
How does triggers work in the Oracle Database?
Oracle Database executes all triggers of the same type before executing triggers of a different type. If you have multiple triggers of the same type on a single table, then Oracle Database chooses an arbitrary order to execute these triggers.
Can you create a recursive trigger on EMP tab?
Do not create recursive triggers. For example, creating an AFTERUPDATEstatement trigger on the Emp_tabtable that itself issues an UPDATEstatement on Emp_tab, causes the trigger to fire recursively until it has run out of memory. Use triggers on DATABASEjudiciously.
When to use a trigger in an UPDATE statement?
An UPDATE statement might include a list of columns. If a triggering statement includes a column list, the trigger is fired only when one of the specified columns is updated. If a triggering statement omits a column list, the trigger is fired when any column of the associated table is updated.
Can a trigger change the name of a column?
Because the trigger uses the BEFOREkeyword, it can access the new values before they go into the table, and can change the values if there is an easily-corrected error by assigning to :NEW.column_name.
When to add a condition under the trigger?
3.You could add an condition under the trigger to check if the “Status is changed” column is equal to true or false.if the “Status is changed”column is equal to true,send the email,if the the “Status is changed” column is equal to false,do nothing. 06-20-2018 03:07 PM