1. MicroSoft SQL-server Some walk through

2. lv/09-2008 Figures & some text from: © Pearson Education Limited 1995, 2005 2 Functions For a DBMS #1 Data storage, retrieval and update A user-accessible catalogue Transaction support Concurrency control services Recovery services

3. lv/09-2008 Figures & some text from: © Pearson Education Limited 1995, 2005 3 Functions For a DBMS #2 Authorization services Support for data communication Integrity services Services to promote data independence Utility services

4. Database – not a single system

5. MS-SQL – Architecture

7. Database – Process organisation

8. Databases - system and user

9. lv/09-2008 Figures & some text from: © Pearson Education Limited 1995, 2005 9 DBMS: ANSI-SPARC

10. Example

11. lv/09-2008 Figures & some text from: © Pearson Education Limited 1995, 2005 11 Description of the 3 levels #1 External Level – Users’ view of the database. – Describes that part of database that is relevant to a particular user. Conceptual Level – Community view of the database. – Describes what data is stored in database and relationships among the data.

12. lv/09-2008 Figures & some text from: © Pearson Education Limited 1995, 2005 12 Description of the 3 levels #2 Internal Level – Physical representation of the database on the computer. – Describes how the data is stored in the database.

13. Entity integritet - Normalisering Afværge – Insert anormalitet – Delete anormalitet – Update anormalitet Hvordan – NF1: primær nøgle + kun én værdi i hver ‘celle’ – NF2: NF1 + del af primær nøgle IKKE alene udpege andre felter i rækken – NF3: NF2 + kun primær nøgle udpege felter i rækken

14. Refential Integritet Ved fremmed nøgler – Ved delete eller update Default Null Cascade No Action