Database BasicsFebruary 22nd 2016

DTC356

Why Do We Need Databases?

• What kinds of problems are databases good at solving?

• When do we need to move from simple physical organization to using a database?

• What does Weinberger say?

Databases:

• Scale: Databases are good at storing large amounts of information

• Organization: Databases work when there is authority and structure

• Accuracy: Databases (when properly managed) return high precision and recall

• **Within the limits of the database record structure

Filter on the way in

• You need to decide on the record structure first.

• Going through the collection and describing everything according to the record structure is labor intensive.

• Once the database is built, searching is quick and relatively easy.

• Changing the record structure is difficult.

• TABLE: A collection of records that use the same field structure

• RECORD: The complete collection of data for one item in the database (row)

• FIELD: An item of data for a record (column)

Vocabulary:

• Unique identifier

• Null

• Key (primary, foreign)

Vocabulary:

http://www.dtc-wsuv.org/cmdc/requirements.html

In small groups: • develop a database record • choose fields • discuss what tasks users will need to perform

Boolean Logic

• Compares the contents of two sets (e.g., fields)

AND (intersection)

OR (union)

NOT (relative compliment)

More on Boolean Logic & Venn Diagrams http://lib.colostate.edu/howto/others/venn.html

How to See your Library Database

Questions to Ask Yourself

• What does a record in this database look like?

• What are the fields in this particular database?

• Can I find a primary key?

• How do I perform operations in this database?