Cursor for updating table in sql oracle
statements might credit one bank account and debit another.
It is important not to allow one operation to succeed while the other fails.
When the session opens a cursor with the FOR UPDATE clause, all rows in the return set will hold row-level exclusive locks.
Other sessions can only query the rows, but they cannot update, delete, or select with FOR UPDATE.
You can manipulate Oracle data flexibly and safely because PL/SQL fully supports all SQL data manipulation statements (except ), transaction control statements, functions, pseudocolumns, and operators.
A searched update statement depends on the table being updated, all of its conglomerates (units of storage such as heaps or indexes), all of its constraints, and any other table named in the WHERE clause or SET expressions.
A CREATE or DROP INDEX statement or an ALTER TABLE statement for the target table of a prepared searched update statement invalidates the prepared searched update statement.
We must declare the cursor with the FOR UPDATE clause to use this feature.
Inside a cursor loop, WHERE CURRENT OF allows the current row to be directly updated.
Then it runs an -- Create a table with all the right IDs, but messed-up names.