In case of relational databases metadata refers to information on their schema and all the other information regarding access, storage, built in programs or any other information about database elements or usage.

What is stored in metadata?

A text document's metadata may contain information about how long the document is, who the author is, when the document was written, and a short summary of the document. Metadata within web pages can also contain descriptions of page content, as well as key words linked to the content.

Is metadata same as schema?

Metadata is 'data about data'. Whereas Schema is the structure/layout of the system. Real world example for Metadata: The extra information generated when you take a picture with your phone such as date, location, etc. Real world example for Schema: The layout of a website such us where is the main title, content, etc.