Database key terms

Database key terms

1. Relational database- tables connected together with primary and foreign keys.

2. Primary key - used to uniquly identify data in a table. E.g. exam number

3. Table- where data is stored.

4. Foreign- when your primary key appears in another table.

5. Field- colnm in a table, one piece of information. E.g. title

6. Record- a row in a table, information about one person or things. E.g. criminal record

7. Flat file database- single tables not connected in anyway

8. Composite key- like a primary key (used to uniquely identify information ) but uses two or more fields.

9. Query- a search to find information in the database.

10. data type- data items defined by the value it can take. E.g. Data/time

11. Field length- number of characters allowed to be entered into a field. E.g. first name= 30 characters

12. Input mask- controls entry into a field. E.g. your postcode _LL9 9LL

13. Data dictionary- plan database and give details of the structure. E.g. field length

14. Normalisation- reducing data that is not required but also separates data into appropriate tables.

15. Database- storing of data in a logical way

16. ERD (entity relationship diagram)- relationship between tables can be 1 to 1, 1 to many or many to many.

17. Validation rule- check the data is valid and reasonable. E.g. school students have to be between 11- 16.