Subschema: A subschema lets the user have access to different areas of applications in which the user designed. The areas that are included in an application are set, types, record types, data items, and data aggregates. Schemas may have many different subschemas' that are all very different.
View and Virtual table:
In SQL, a view is a virtual table based on the result-set of an SQL statement.
A view contains rows and columns, just like a real table. The fields in a view are fields from one or more real tables in the database.
You can add SQL functions, WHERE, and JOIN statements to a view and present the data as if the data were coming from one single table.
https://sqlite.org/lang_createvtab.html (This link for virtual table). Please correct me if I m wrong at any point. Yeah. :)