About
A SQL schema is two things:
- It'is a persistent, named collection of metadata (known as information_schema) that defines a schema
- a scope because a schema is part of the object identifier.
A SQL Schema is:
- created via the SQL CREATE statement.
- altered via the SQL ALTER statement
Scope / Level
Most providers have a limited number of levels; for example, most databases have either;
- one level (“schemas”)
- or two levels (“database” and catalog.