Three Schema Model
- ANSI/SPARC introduced the three schema model in 1975
- It provides a framework describing the role and purpose of data modeling
1. External schema or user view
- Representation of how users view the database
2. Conceptual schema
- A logical view of the database containing a description of all the data and relationships
- Independent of any particular means of storing the data
- One conceptual schema usually contains many different external schemas
3. Internal schema
- A representation of a conceptual schema as physically stored on a particular product
- A conceptual schema can be represented by many different internal schemas