X | IX | S | IS | |
---|---|---|---|---|
X | Conflict | Conflict | Conflict | Conflict |
IX | Conflict | Compatible | Conflict | Compatible |
S | Conflict | Conflict | Compatible | Compatible |
IS | Conflict | Compatible | Compatible | Compatible |
- A shared (S) lock permits the transaction that holds the lock to read a row.
- An exclusive (X) lock permits the transaction that holds the lock to update or delete a row.
- An intention shared lock (IS) indicates that a transaction intends to set a shared lock on individual rows in a table.