Terminology
	v The structure of a data base is called a database schema v The schema specifies … ; The list of table names forming the database ; For each table, the fields of its records ; For each field, its attributes or properties, i.e. data type, key or not key, default value, etc. v A database as the word is normally used, i.e. tables with specific contents, is known as a database instance (of a data base schema) v There can be many instances of a single database schema