A lock is a certain type of software mechanism by using which, we can restrict other users from using the data resource. There are four type of locks given in JDBC that are described below.
- Row and Key Locks: These type of locks are used when we update the rows.
- Page Locks: These type of locks are applied to a page. They are used in the case, where a transaction remains in the process and is being updated, deleting, or inserting some data in a row of the table. The database server locks the entire page that contains the row. The page lock can be applied once by the database server.
- Table locks: Table locks are applied to the table. It can be applied in two ways, i.e., shared and exclusive. Shared lock lets the other transactions to read the table but not update it. However, The exclusive lock prevents others from reading and writing the table.
- Database locks: The Database lock is used to prevent the read and update access from other transactions when the database is open.
