Oracle triggers are database objects that automatically perform actions when a specific event occurs in a table, such as inserting, updating, or deleting a record. To create a trigger, use the syntax CREATE TRIGGER
ON FOR
ASBEGIN END;. Triggers can insert, update, or delete records in another table, call procedures or functions, and execute user-defined code.
Oracle Database Trigger Creation Guide
What is an Oracle trigger?
Oracle trigger is a database object that automatically performs a series of actions when a specific event occurs in a table, such as inserting, updating, or deleting a record. Triggers can be used to validate data, perform calculations, or record audit events, etc.
How to create a trigger
To create an Oracle trigger, use the following syntax:
<code class="sql">CREATE TRIGGER <触发器名称> ON <表名称> FOR <事件> AS BEGIN -- 执行触发的动作 END;</code>Copy after loginTrigger event
The following events can be defined for triggers:
- INSERT: Triggered when a new record is inserted
- UPDATE: at
- DELETE triggered when an existing record is updated: Triggered when an existing record is deleted
Trigger action
The trigger can perform the following operations:
- Insert: Insert a new record into another table
- Update: Update another Existing records in one table
- Delete:Delete records from another table
- Call a procedure or function:Execute user-defined code
Trigger Example
For example, the following trigger stores employee names into the "AuditLog" table when a new record is inserted into the "Employees" table :
<code class="sql">CREATE TRIGGER audit_employee_insert ON Employees FOR INSERT AS BEGIN INSERT INTO AuditLog (action, table_name, record_id, employee_name) VALUES ('INSERT', 'Employees', NEW.employee_id, NEW.employee_name); END;</code>Copy after loginNote:
- Trigger names must be unique.
- Triggers can contain multiple actions.
- Triggers can be disabled during DDL (Data Definition Language) operations such as creating or dropping tables.
- Triggers can be created as many times as needed.
The above is the detailed content of How to write trigger in oracle database. For more information, please follow other related articles on the PHP Chinese website!
Related labels：source：php.cnPrevious article：How to check the oracle database listening port Next article：How to run sql in oracle databaseStatement of this WebsiteThe content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cnLatest Articles by Author
JAVA Beginner's Video Tutorial2517274
Latest DownloadsMore>
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
