Table of Contents
Where is database triggers used?
A database trigger is procedural code that is automatically executed in response to certain events on a particular table or view in a database. The trigger is mostly used for maintaining the integrity of the information on the database.
Should we use database triggers?
Triggers are a requirement for any complex data integrity rules. These cannot be enforced anywhere except the database or you will have data integrity problems. They are also the best place for auditing unless you don’t want to capture all changes to the database (which is the problem of auditing from the application).
Are SQL triggers bad practice?
Triggers are generally over-used in SQL Server. They are only rarely necessary, can cause performance issues, and are tricky to maintain If you use them, it is best to keep them simple, and have only one operation per trigger.
Under which two circumstances do you design database triggers?
Under which circumstance do you design database triggers? To duplicate the functionality of other triggers. To replicate built-in constraints in the Oracle server such as primary key and foreign key. When a specific operation is performed, related actions are performed.
Why are triggers used?
Because a trigger resides in the database and anyone who has the required privilege can use it, a trigger lets you write a set of SQL statements that multiple applications can use. It lets you avoid redundant code when multiple programs need to perform the same database operation.
Do SQL triggers affect performance?
Yes, a table with a trigger will not perform as well as it would without it.
How do you trigger a database?
create trigger [trigger_name]: Creates or replaces an existing trigger with the trigger_name. [before | after]: This specifies when the trigger will be executed. {insert | update | delete}: This specifies the DML operation. on [table_name]: This specifies the name of the table associated with the trigger.
What is a database trigger and how does it work?
What is a Database Trigger? A database trigger is special stored procedure that is run when specific actions occur within a database. Most triggers are defined to run when changes are made to a table’s data. Triggers can be defined to run instead of or after DML (Data Manipulation Language) actions such as INSERT, UPDATE, and DELETE.
Where are triggers stored in SQL Server?
Figure 15 – 1. Triggers. Notice that triggers are stored in the database separately from their associated tables. Triggers can be defined only on tables, not on views. However, triggers on the base table(s) of a view are fired if an INSERT, UPDATE, or DELETE statement is issued against a view.
What are triggers and why should you use them?
Triggers are useful when you want to identify when discrete events occur, and it allows for the user to drill down into the metrics of that event. Triggers also are useful for manipulating data when that data is present. This type of triggers are extremely useful when external data is imported from outside sources.
Can SQL statements within an Oracle Forms application trigger a trigger?
SQL statements within an Oracle Forms application, as with any database application, can implicitly cause the firing of any associated database trigger. For more information about Oracle Forms and Oracle Forms triggers, see theOracle Forms User’s Guide. Triggers vs. Declarative Integrity Constraints