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.