- Can we use DML statement in trigger?
- Is commit needed after insert?
- What is Pragma Autonomous_transaction?
- Can we use Pragma Autonomous_transaction in trigger?
- What is a mutating table?
- Can we commit inside a trigger?
- What are the after trigger?
- Can we commit after rollback?
- Can rollback or commit issued inside a trigger code?
- What is mutating in the trigger?
- What is after update trigger?
- What is bulk collect in Oracle?
- What is statement level trigger?
- What is compound trigger?
- What will happen when a rollback statement is executed inside a trigger?
- Can we use commit in procedure?
- What is difference between cursor and ref cursor?
- How do you overcome a mutating trigger in Oracle?
- How are mutating table errors avoided?
- What is the meaning of mutating?
- What is the difference between after and before trigger?
Can we use DML statement in trigger?
You can write triggers that fire whenever one of the following operations occurs: DML statements ( INSERT , UPDATE , DELETE ) on a particular table or view, issued by any user.
DDL statements ( CREATE or ALTER primarily) issued either by a particular schema/user or by any schema/user in the database..
Is commit needed after insert?
So yes, by default, if you’re just using INSERT , the records you insert will be committed, and there is no point trying to roll them back. (This is effectively the same as wrapping each statement between BEGIN and COMMIT .)
What is Pragma Autonomous_transaction?
The AUTONOMOUS_TRANSACTION pragma changes the way a subprogram works within a transaction. A subprogram marked with this pragma can do SQL operations and commit or roll back those operations, without committing or rolling back the data in the main transaction. … They pass information to the compiler.
Can we use Pragma Autonomous_transaction in trigger?
The trigger has pragma autonomous_transaction, and trigger works as intended. …
What is a mutating table?
A mutating table is a table that is currently being modified by an UPDATE, DELETE, or INSERT statement, or it is a table that might need to be updated by the effects of a declarative DELETE CASCADE referential integrity constraint.
Can we commit inside a trigger?
Trigger should not commit and cannot commit. Committing in a trigger usually raises an exception unless it happens into autonomous transaction. When you open connection, Oracle creates session for it.
What are the after trigger?
After Trigger (using FOR/AFTER CLAUSE) This trigger fires after SQL Server completes the execution of the action successfully that fired it.
Can we commit after rollback?
A transaction is a sequence of SQL statements that Oracle Database treats as a single unit. … After you commit the transaction, the changes are visible to other users’ statements that execute after the commit. You can roll back (undo) any changes made during the transaction with the ROLLBACK statement (see ROLLBACK.
Can rollback or commit issued inside a trigger code?
Changes made within triggers should thus be committed or rolled back as part of the transaction in which they execute. For this reason, triggers are NOT allowed to execute COMMIT or ROLLBACK statements (with the exception of autonomous triggers).
What is mutating in the trigger?
A mutating table error (ORA-04091) occurs when a row-level trigger tries to examine or change a table that is already undergoing change (via an INSERT, UPDATE, or DELETE statement). In particular, this error occurs when a row-level trigger attempts to read or write the table from which the trigger was fired.
What is after update trigger?
MySQL AFTER UPDATE triggers are invoked automatically after an update event occurs on the table associated with the triggers. The following shows the syntax of creating a MySQL AFTER UPDATE trigger: CREATE TRIGGER trigger_name AFTER UPDATE ON table_name FOR EACH ROW trigger_body.
What is bulk collect in Oracle?
A bulk collect is a method of fetching data where the PL/SQL engine tells the SQL engine to collect many rows at once and place them in a collection. The SQL engine retrieves all the rows and loads them into the collection and switches back to the PL/SQL engine.
What is statement level trigger?
A statement-level trigger is fired whenever a trigger event occurs on a table regardless of how many rows are affected. In other words, a statement-level trigger executes once for each transaction. For example, if you update 1000 rows in a table, then a statement-level trigger on that table would only be executed once.
What is compound trigger?
A compound trigger is a single trigger on a table that enables you to specify actions for each of four timing points: Before the firing statement. Before each row that the firing statement affects. After each row that the firing statement affects.
What will happen when a rollback statement is executed inside a trigger?
When the rollback trigger is executed, Adaptive Server aborts the currently executing command and halts execution of the rest of the trigger.
Can we use commit in procedure?
There’s no autocommit , but it’s possible to set commit command into stored procedure.
What is difference between cursor and ref cursor?
2 Answers. A cursor is really any SQL statement that runs DML (select, insert, update, delete) on your database. A ref cursor is a pointer to a result set. This is normally used to open a query on the database server, then leave it up to the client to fetch the result it needs.
How do you overcome a mutating trigger in Oracle?
Fixing the mutating table errorFirst, declare an array of customer record that includes customer id and credit limit.Second, collect affected rows into the array in the row-level trigger.Third, update each affected row in the statement-level trigger.
How are mutating table errors avoided?
Use autonomous transactions – You can avoid the mutating table error by marking your trigger as an autonomous transaction, making it independent from the table that calls the procedure.
What is the meaning of mutating?
/mjuːˈteɪt/ to develop new physical characteristics because of a permanent change in the genes. These changes can happen naturally or can be produced by the use of chemicals or radiation: These bacteria have mutated into forms that are resistant to certain drugs.
What is the difference between after and before trigger?
Before triggers execute before the data has been committed into the database. … After triggers execute after the data has been inserted or updated in the database. Usually after triggers are used because you need access to a formula field or the Id in the case of an insert.