Following standard objects don’t support DML operations, but it supports SOQL query.
- AccountTerritoryAssignmentRule
- AccountTerritoryAssignmentRuleItem
- ApexComponent
- ApexPage
- BusinessHours
- BusinessProcess
- CategoryNode
- CurrencyType
- DatedConversionRate
- NetworkMember (allows update only)
- ProcessInstance
- Profile
- RecordType
- SelfServiceUser
- StaticResource
- Territory2
- UserAccountTeamMember
- UserTerritory
- WebLink