What does on delete no action?

What does on delete no action?

What does on delete no action?

NO ACTION means that nothing will happen when you delete from your Subject table to the Topic table. In that case, if there is a row in Topic for a given SubjectId you cannot delete from it without breaking referential integrity, so the Delete will be rolled back.

Is on delete No action default?

By default, SQL Server applies ON DELETE NO ACTION if you don’t explicitly specify any action.

Can we use delete without WHERE clause?

DELETE Syntax Notice the WHERE clause in the DELETE statement. The WHERE clause specifies which record(s) should be deleted. If you omit the WHERE clause, all records in the table will be deleted!

What happens when no condition is specified in delete statement?

If you run a DELETE statement with no conditions in the WHERE clause, all of the records from the table will be deleted.

How do I use the default delete set?

SET DEFAULT: Using the SET DEFAULT option of the ON UPDATE and ON DELETE clauses specifies that, if the referenced values in the parent table are updated or deleted, the related values in the child table with FOREIGN KEY columns will be set to its default value.

What happens if you run a delete command that does not contain a WHERE clause?

What happens if you run a DELETE command that does not contain a WHERE clause? All rows will be deleted from the table.

What will happen if you exclude delete command without WHERE clause?

Delete statement without WHERE clause will delete all the records of the table and without proper rollback mechanism, your data could be lost forever.

What will happen if we forget to specify the WHERE clause in the delete query?

Similarly, as mentioned above if you do not specify the WHERE clause in the DELETE statement all the rows from the table will be deleted.

What is difference between truncate and delete command?

The DELETE statement removes rows one at a time and records an entry in the transaction log for each deleted row. TRUNCATE TABLE removes the data by deallocating the data pages used to store the table data and records only the page deallocations in the transaction log. 6. DELETE command is slower than TRUNCATE command.

How do you use Restrict on delete?

The ON DELETE clause says that if a particular primary key ID value in the CUSTOMERS table is deleted, this action shall be prevented (this is the “restrict” part) if there is any row in the ORDERS table which has a foreign key that matches the value of the CUSTOMER table ID value.

How do DB2 databases know the difference between on delete restrict and no action?

The databases IBM DB2, PostgreSQL (for INITIALLY DEFERRED constraints), HSQLDB, and SQLite know the difference between ON DELETE RESTRICT and ON DELETE NO ACTION. In databases in which the two clauses are different: NO ACTION constraint rules are checked after the statement and all other operations (such as triggers) are completed.

How do I delete a row in DB2?

Introduction to Db2 DELETE statement The DELETE statement allows you to delete one or more rows from a table. The following illustrates the syntax of the DELETE statement: DELETE FROM table_name [ WHERE condition];

When does DB2 add predicates to the DELETE statement?

When an application-period table is the target of a DELETE statement and the value in effect for the CURRENT TEMPORAL BUSINESS_TIME special register is not the null value, Db2 adds the following additional predicates to the statement:

How does DB2 handle rows with multilevel security?

When you delete rows from a table with multilevel security, Db2 compares the security label of the user (the primary authorization ID) to the security label of the row. The delete proceeds according to the following rules: