Where is the component monitor data stored in the database (e.g. availability of a monitor for a given period)?

Depends on the component monitor type. Most component monitor data is stored in the "Orion.APM.PortEvidence" table (performance counters, User Experience Monitors, etc.). The "Orion.APM.DynamicEvidence" table is where script monitor results are stored, and the "Orion.APM.ProcessEvidence" table is where information related to processes and services are stored.

Thanks for that.

Looking around the database is it safe to assume that the availability of a component monitor(e.g. HTTP monitor) is found on the APM_ComponentStatus tables?

I can also see the availability column in the APM_ComponentStatus table is an integer, is there reference table which details what each integer means?

Perhaps the best and easiest way to answer those questions is with some simple examples that demonstrate how to gather application or component availability via SQL.

Application Availability

SELECT  TOP 10000 APM_ApplicationAvailability.PercentAvailability AS ApplicationAvailability,
APM_AlertsAndReportsData.ApplicationName AS Application_Name 


FROM 
APM_AlertsAndReportsData INNER JOIN APM_ApplicationAvailability ON (APM_AlertsAndReportsData.ApplicationId = APM_ApplicationAvailability.ApplicationID)

Component Availability

SELECT  TOP 10000 APM_ComponentAvailability.PercentAvailability AS ComponentAvailability,
APM_AlertsAndReportsData.ComponentName AS ComponentName 


FROM 
APM_AlertsAndReportsData INNER JOIN APM_ComponentAvailability ON (APM_AlertsAndReportsData.ComponentId = APM_ComponentAvailability.ComponentID)