SLC deletion without manipulating backend RDB

[dolow]

Current CRUD interfaces using QueryBuilder are persistent to backend RDB and I understand that it is necessary to keep atomicity between cache and DB record.
However, sometimes I wanted to delete only second level cache with condition.

If it is OK to add new interface or option, please let me work for this.
Supporting Update and Create clause breaks atomicity between cache and DB records.
I thought it is against to this module's policy so I focused to Delete operation in this topic.