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Introduction to Information and
Computer Science
Databases and SQL
Lecture b
This material (Comp4_Unit6b) was developed by Oregon Health & Science University, funded by the Department of Health and
Human Services, Office of the National Coordinator for Health Information Technology under Award Number
IU24OC000015.
Databases and SQL
Learning Objectives
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•
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Define and describe the purpose of databases (Lecture a)
Define a relational database (Lecture a)
Describe data modeling and normalization (Lecture b)
Describe the structured query language (SQL) (Lecture c)
Define the basic data operations for relational databases and how to
implement them in SQL (Lecture c)
• Design a simple relational database and create corresponding SQL
commands (Lecture c)
• Examine the structure of a healthcare database component (Lecture
d)
Health IT Workforce Curriculum
Version 3.0/Spring 2012
Introduction to Information and Computer Science
Databases and SQL
Lecture b
2
Representing Data
• Identify entities (tables)
• Identify attributes (columns)
• Identify table relationships
6.8 Figure: Entity-Relationship Diagram (ER diagram) (PD-US, 2012)
Health IT Workforce Curriculum
Version 3.0/Spring 2012
Introduction to Information and Computer Science
Databases and SQL
Lecture b
3
Relationships
• One-to-one
• One-to-many
• Many-to-many
6.9 Figure: One-to-many relationship (PD-US, 2012)
Health IT Workforce Curriculum
Version 3.0/Spring 2012
Introduction to Information and Computer Science
Databases and SQL
Lecture b
4
Identify the Data
• A contact:
– Person’s first name
– Person’s last name
– Company name
– Company address
– Company city
– Company state
Health IT Workforce Curriculum
Version 3.0/Spring 2012
Introduction to Information and Computer Science
Databases and SQL
Lecture b
5
Simple Database Structure
• One entity/table
• Create a unique row identifier
• Attributes:
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–
–
–
–
–
–
Key (integer)
Person’s first name (varchar)
Person’s last name (varchar)
Company name (varchar)
Company address (varchar)
Company city (varchar)
Company state (char)
Health IT Workforce Curriculum
Version 3.0/Spring 2012
Contact
Key
PersonFirstName
PersonLastName
CoName
CoAddress
CoCity
CoState
6.10 Table: Contact attributes (PD-US, 2012)
Introduction to Information and Computer Science
Databases and SQL
Lecture b
6
Contact Table
Key
PersonFirst
Name
PersonLast
Name
CoName
CoAddress
CoCity
1
Bill
Robeson
Community
Hospital, Inc.
1312 Main
Portland OR
2
Albert
Brookings
Community
Hospital Inc.
1312 Main St.
Portland OR
CoState
6.11 Table: Contact table (PD-US, 2012)
Problems:
– Company data is stored in multiple locations
– Company data may be inconsistent
– Significant work to update data when company
information changes
Health IT Workforce Curriculum
Version 3.0/Spring 2012
Introduction to Information and Computer Science
Databases and SQL
Lecture b
7
Database Normalization
• Prevent data inconsistency
• Prevent update errors
• Eliminate data redundancy
Health IT Workforce Curriculum
Version 3.0/Spring 2012
Introduction to Information and Computer Science
Databases and SQL
Lecture b
8
Normalized Database Structure
Two tables: Person and Company
Each has a unique row identifier – a primary key
Need to link the company to the contact
6.12 Figure: Normalized database structure (PD-US, 2012)
Health IT Workforce Curriculum
Version 3.0/Spring 2012
Introduction to Information and Computer Science
Databases and SQL
Lecture b
9
New Tables
Person Table
ContactKey
FirstName
LastName
CompanyKey
1
Bill
Robeson
1
2
Albert
Brookings
1
Company Table
Company
Key
Name
Address
City
State
1
Community
Hospital, Inc.
1312 Main
Portland
OR
6.13 Tables: New tables using same data from Table 6.5 (PD-US, 2012)
Health IT Workforce Curriculum
Version 3.0/Spring 2012
Introduction to Information and Computer Science
Databases and SQL
Lecture b
10
How Do We Do This?
• Database Management System
– Create
– Maintain
– Use
• Many available (NOT an exhaustive list)
– Oracle
– Microsoft SQL Server
– IBM DB2
– MySQL
– PostgreSQL
Health IT Workforce Curriculum
Version 3.0/Spring 2012
Introduction to Information and Computer Science
Databases and SQL
Lecture b
11
Building a Database
• Database Management System Tools
– Create tables
– Create relationships
– Control access
– More…
• Structured Query Language (SQL)
– Database management
– Access to data
Health IT Workforce Curriculum
Version 3.0/Spring 2012
Introduction to Information and Computer Science
Databases and SQL
Lecture b
12
Databases and SQL
Summary – Lecture b
• Databases can be modeled using entity
relationship diagrams
• Relationships can have 3 different types of
cardinality
• Normalization avoids duplicate data
• Relationships are created using foreign keys
Health IT Workforce Curriculum
Version 3.0/Spring 2012
Introduction to Information and Computer Science
Databases and SQL
Lecture b
13
Databases and SQL
References – Lecture b
References
•
Chen, P. P.-S. (1976). The Entity-Relationship Model - Toward a Unified View of Data. ACM Transactions on
Database Systems, 1(1).
•
International Organization for Standardization. (2008). Information technology -- Database languages -- SQL (No.
ISO/IEC 9075-(1-4,9-11,13,14)).
•
Kent, W. (1983). A simple guide to five normal forms in relational database theory. Communications of the ACM,
26(2).
Charts, Tables, Figures
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6.8 Figure: Entity-Relationship Diagram (ER diagram) (PD-US, 2012)
•
6.9 Figure: One-to-many relationship (PD-US, 2012)
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6.10 Table: Contact attributes (PD-US, 2012)
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6.11 Table: Contact table (PD-US, 2012)
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6.12 Figure: Normalized database structure (PD-US, 2012)
•
6.13 Tables: New tables using same data from Table 6.5 (PD-US, 2012)
Health IT Workforce Curriculum
Version 3.0/Spring 2012
Introduction to Information and Computer Science
Databases and SQL
Lecture b
14