# Lock compatibility

This table lists compatibility between lock types. `+` means the lock types are compatible, while `-` means they are incompatible.

Table 1. Lock Compatibility Matrix
| Shared | Update | Exclusive
Shared | + | + | -
Update | + | - | -
Exclusive | - | - | -

Parent topic: Types and scope of locks in Derby systems
Related concepts
Exclusive locks
Shared locks
Update locks
Notes on locking
Related reference
Scope of locks