Relational Theory by Marcos Benevides
:ID: abcb3048-34a5-4561-885c-74b8285924ac
It was late in 1968 that Codd, a mathematician by training, first realized that the discipline of mathematics could be used to inject some solid principles and rigor into a field, database management, that prior to that time was all too deficient in any such qualities. His original definition of the relational model appeared in an IBM Research Report in 1969 (…) (Date 2015).
Date’s Review of Codd’s Original Algebra
The relational model defines a database abstraction based on relations to avoid maintenance overhead. It has three key ideas:
- Store database in simple data structures (relations).
- Physical storage left up to the DBMS implementation.
- Access data through a high-level language, where the DBMS figures out best execution strategy.
Structure
The definition of relations and their contents independent of their physical representation
Types (or Domains)
n-Ary Relations
Attributes & Tuples
Keys
- Candidate
- Primary
- Foreign
Integrity
Ensure the database’s contents satisfy certain constraints
Entity Integrity
Referential Integrity
Manipulation
Programming interface for accessing and modifying a database’s contents
- Relational Algebra
- Relational Assignment