Definition - What does Schema Change mean?
A schema change is an alteration made to a collection of logical structures (or schema objects) in a database. Schema changes are generally made using structured query language (SQL) and are typically implemented during maintenance windows.
Techopedia explains Schema Change
A schema is a general blueprint for how a database is structured. This includes a number of different tables, fields, keys and other organizational factors that, if altered, can cause complications in the database. Therefore, executable scripts are used to implement schema changes so that they can be properly implemented.