Database Goodness

College of Alamedapmcdermott@peralta.edu

Copyright © 2008 Patrick McDermott

Berthe Morisot (1841–95)The Cradle, 1872

Why DB?• Retrieve

– Find The Data• Distribute

– Let Many see it• Security

– Control who sees It

Database Efficiency• Absence of Redundancy• Minimal use of null values• Prevention of Loss of Information

Redundancy• Waste Space• Gets Out of Sync• UK: Unemployed• DBA: Unnecessary

Flat File Headaches• Multiple Values

– Either multiple rows or columns, or cram it• Update Anomaly

– Must find and update all repetitions• Insertion Anomaly

– Can’t add one without the other• Deletion Anomaly

– Delete one deletes the other

Redundancy• Example from 1996, using Library of

Congress as example:• A certain “approach wastes about 1.6

gigabytes of space, just for the address field!”

• “Indeed, the issue of redundancy alone is quite enough to convince a database designer to avoid the flat database approach.”

Integrity• Referential Integrity• No Orphans

Referential Integrity• Restrict• Cascade• Set to null

Concurrency Control• Lost update• Uncommitted dependency• Inconsistent analysis

Programming Goodness I1. Openness of the data refers to the capability of other

routines or applications to make sense of the data file without access to your source code.

2. Complex data models refers to the technology’s capability to handle applications that have complex data entities and relationships.

3. Multiuser refers to the capability of multiple threads, applications, and users to access the data simultaneously.

4. Performance refers to the speed with which data can be read from and written to the database.

5. Scalability and capacity refers to the database’s capability to sustain good performance as the amount of data increases.

…

Programming Goodness II6. Set-based operations in code indicates whether the

technology offers set-based operations in its programming model.

7. Set-based operations at the server refers to the capability of the technology to process data at the server without having to send it all to the client machine processed.

8. Embeddable with your application indicates how easy or difficult it would be to ship this technology with a commercial application.

9. Data validation/integrity refers to the database’s capability to validate the data to ensure the integrity of the data.

10.Code-to-functionality ratio refers to how much code you have to write to the database functionality you get from that code.