3.9 Data & Databases
- Database systems: computerized mechanisms to store and retrieve data.
- Relational databases: data is represented as tables linked based on common keys (to avoid redundancy)
![In the relational model, records are “linked” using virtual keys not stored in the database but defined as needed between the data contained in the records](www/516px-Relational_key_SVG.png)
In the relational model, records are “linked” using virtual keys not stored in the database but defined as needed between the data contained in the records
Source: (Wikipedia)