A schema in computer programming is the organisation or structure for a database.
It can also be used in regards to maths where a schema is a formal expression of an inference rule for artificial intelligence computing.
A schema is created through modelling and is used when talking about both relational databases and object oriented databases.
Basically a schema is the blueprint of how a database is constructed, although it can be said to be a set of formulas called integrity constraints imposed on a database. Integrity constraints are designed to ensure the compatibility between parts of the schema and all constraints are expressible in the same language.
Certain requirements can influence the detailed structure of schemas such as overlap preservation where each of the overlapping elements specified in the input mapping.
Extended overlap preservation sees that source specific elements that are associated with a source’s overlapping elements are passed through to the database schema.