Please find the Availability STATE information below

1. ACTIVE = 1 corresponds to the Device in UP state.

2. DOWN = 2 corresponds to the Device in DOWN state.

3. DEPENDENT_UNAVAILABLE = 3 corresponds to the DEPENDENCY DEVICE's down state.

4. ON_HOLD = 4 corresponds to the state when the Device is UNMANAGED ( like via Actions -> UnManage )

5. ON_MAINTENANCE = 5 corresponds to the device state when it is part of a DOWNTIME SCHEDULE that is in progress

6. PARENT_DOWN = 6 corresponds to the interface state when the parent ( device on which the INTERFACE is present) is down

7. PARENT_UNMANAGED = 7 corresponds to the interface state when the parent ( device to which the INTERFACE is present ) is UNMANAGED 

In the database,this STATE column is present in the ManagedObject Database table