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The four main types of triggers are: Row-level trigger: This gets executed before or after any column value of a row changes. Column-level trigger: This gets executed before or after the specified column changes. For each row type: This trigger gets executed once for each row of the result set affected by an insert/update/delete.
A database trigger is like a stored procedure that Oracle Database invokes automatically whenever a specified event occurs. It is a named PL/SQL unit that is stored in the database and can be invoked repeatedly. Unlike a stored procedure, you can enable and disable a trigger, but you cannot explicitly invoke it.
If the data is being persisted in a modern database then Change Data Capture is a simple matter of permissions. Two techniques are in common use: Tracking changes using database triggers; Reading the transaction log as, or shortly after, it is written. If the data is not in a modern database, CDC becomes a programming challenge.
In relational databases, the log trigger or history trigger is a mechanism for automatic recording of information about changes inserting or/and updating or/and deleting rows in a database table. It is a particular technique for change data capturing , and in data warehousing for dealing with slowly changing dimensions .
Triggers are fully supported and can be attached to tables. Triggers can be per-column and conditional, in that UPDATE triggers can target specific columns of a table, and triggers can be told to execute under a set of conditions as specified in the trigger's WHERE clause. Triggers can be attached to views by using the INSTEAD OF condition ...
Yes (Row-level locking) Yes Yes API & GUI & SQL: Yes Advantage Database Server: Yes ... OpenEdge ABL Database engine does not and is handled via database triggers.
The engine supports stored procedures, user functions (using Watcom SQL, T-SQL, Java, or C/C++), triggers, referential integrity, row-level locking, replication, high availability, proxy tables, and events (scheduled and system events). Strong encryption is supported for both database files and client-server communication.
1 Addition of Row/Statement Level Triggers. 2 standards. 1 comment. 3 a musing. 1 comment. 4 mutating table errors. 1 comment. ... Talk: Database trigger. Add languages.