These objects doesn’t support DML operations from Apex, but it supports SOQL(Querying)

1. AccountTerritoryAssignmentRule
2. AccountTerritoryAssignmentRuleItem
3. ApexComponent
4. ApexPage
5. BusinessHours
6. BusinessProcess
7. CategoryNode
8. CurrencyType
9. DatedConversionRate
10. ProcessInstance
11. Profile
12. RecordType
13. SelfServiceUser
14. StaticResource
15. UserAccountTeamMember
16. UserTerritory
17. WebLink