Data model Schema Instance | Skeleton structure of the database

Data model Schema and Instance

• The data which is stored in the database at a particular moment is called an instance of the database.
• The overall design of a database is called schema
• A database schema is the skeleton structure of the database. It represents the logical view of the entire database.
• A schema includes schema objects such as tables, foreign keys, primary keys, views, columns, data types, stored procedures, etc.
• A database schema can be represented using a visual diagram. This diagram shows the database objects and their relationship with each other.
• A database schema is designed by database designers so that the programmers whose software will interact with the database. The process of database creation is called data modeling.

A schema diagram can display some aspects of a type of schema named record types, data types and constraints. Other aspects cannot be specified through a schema diagram. The given figures, for example, show neither the data type of each data item nor the relationship between the different files.

In the database, the actual data changes quite frequently. For example, in the given data, whenever we add a new grade or add a student, the database changes. The data at a particular moment of time is called an instance of the database.