Designing Databases for Biological Research

Brian R. Mitchell

Fall 2006

Introduction

• Participants

• Syllabus• Website:

http://www.uvm.edu/~bmitchel/databases.html

• Database options at UVM

What is a Database?

• Definition

• Keys

• Structured Query Language (SQL)

• Relationships

Relationships

• One-to-one

Technicians Contact_Info

Amy Amy’s address

Joe Joe’s Address

Fred Fred’s Address

Relationships

• One-to-many

Site Count_Data

286 (+ site fields) 286 (species 1)

286 (species 2)

286 (species 3)

Relationships

• Many-to-many

Students Classes

Ralph BIO 165

Susan NR 385?

Relationships

• Many-to-many

Students Classes

Ralph BIO 165

Susan NR 385

Schedule

Student & Class

Why Use a Database?

Naming Conventions

• Keep it short

• Make it meaningful

• No spaces – use underscores “_”

• Avoid @#%$*& special characters

• Be consistent

Naming Fields

• Be specific

• One piece of information per field

• No calculated fields

• Identify your keys

Naming Objects

• Conventional abbreviations for objects:• Tables

– tbl = data table– tlu = lookup table– xref = linking table

• Queries = qry• Forms

– frm = form– frm_sub or fsub = subform

• Reports– rpt = report– rpt_sub or rsub = subreport

• Pages = pag (not widely used)• Macros = mac (not widely used)• Modules = mod

Avoid Reserved Words

avg key propertycount max sectioncurrency memo setdate min sumdesc name time exists number typegroup order valueindex percent year

Data Types

• AutoNumber• Currency• Date/Time• Hyperlink• Memo• Number• OLE• Text• Yes/No

Database Design

• Single Database or Front End / Back End?

• Normalization

Database Design

• Non-normalized

Spreadsheet-style

Site Date Observer Bird24 7/1/04 BRM BTBW24 7/1/04 BRM OVEN24 7/1/04 BRM YBSA

Database Design

• First Normal Form (1NF)

Each field contains one value

NO YES

Coordinates UTM_E & UTM_N

Birds seen Separate table

Database Design

• Second Normal Form (2NF)

If you have a composite key, no data relates to one of the keys

Example from Northwind database

Database Design

• Third Normal Form (3NF)

Information in the table must not be related to a non-key field

Example from Northwind database

Database Design

• Plan your database– Why bother?– Iterative process– Tables– Relationships– Fields– Rules

Exercise

Tables FieldsSpecies Species_ID, Common, SciLocation Habitat, CoordinateVisit Time, Weather, DateSurvey Minute, species, vis/aud

Multiple visits to each location10 minute count during each visit: listens for each individual

of each species that can see or hear, records species, minute during count, visual/auditory