The ANSI SPARC architecture divided into three levels:
- External level
- Conceptual level
- Internal level
(Three levels ANSI SPARC Database System)
Internal Level
- This is the lowest level of the data abstraction.
- It describes how the data are actually stored on storage devices.
- It is also known as a physical level.
- The internal view is described by internal schema.
- Internal schema consists of definition of stored record, method of representing the data field and access method used.
Conceptual Level
- This is the next higher level of the data abstraction.
- It describes what data are stored in the database and what relationships exist among those data.
- It is also known as a logical level.
- Conceptual view is defined by conceptual schema. It describes all records and relationship.
External Level
- This is the highest level of data abstraction.
- It is also known as view level.
- It describes only part of the entire database that a particular end user requires.
- External view is describes by external schema.
- External schema consists of definition of logical records, relationship in the external view and method of deriving the objects from the conceptual view.
- This object includes entities, attributes and relationship.
