Database Schema vs instance
This video clearly distinguishes between the schema and instance in a Database Management System (DBMS). The schema refers to the overall design or structure of a database, outlining how data is organised and the relationships between different data elements, such as table attributes. It is a logical view of the database and is categorised into physical, logical, and view schemas, each describing the database at a different level of abstraction.
In contrast, a DBMS instance represents the actual data present in the database at a specific moment in time, which is dynamic and changes as data is added, deleted, or updated. Essentially, the schema is the unchanging blueprint, while the instance is the ever-evolving content held within that blueprint.