MIS 320 Kraig Pencil Summer 2014 Database Design MIS 320 Kraig Pencil Summer 2014

Game Plan Introduction Data base design Database scenario Key questions/answers

A. Introduction Remember … ? CNN: Internet is “Top innovation” of past 25 years (1/18/05) But Kraig Pencil says … The relational database is equally important Really? Why? The Internet would not be nearly as successful without relational databases providing rich information.

A. Introduction You can ask a database questions How many cans of chicken soup do we have in inventory? How large is the average pay raise in each department? Who are my best/worst customers? What else have I-Pod buyers also purchased? Is this airline passenger a known terrorist? Who has friended Gayle Zhang? Who else might Gayle want to consider friending? With the right data and a well-designed database, you can ask anything.

A. Introduction Who works with databases? Database programmers Database analysts Database designers Database administrators Data administrators Website designers/programmers Many non-IT users! Marketers Financial analysts Human resources managers …. And more

A. Introduction What does an organization do with data/information? Capture, cradle, and process transaction data/information e.g., TPS Use information to make decisions e.g., DSS “Oversee” the information e.g., Who can view or use what info?, How to back up info?, How long to retain info? What can help support the above? A database management system

B. Business Scenario Is data management a problem? For generations we stored information in filing cabinets, then in Excel spreadsheets. But as the amount of data has grown those methods have become … Inefficient – and expensive – to store and gather data Unable to support for decision making based on data  A database management system is needed to support business !!!

B. Business Scenario Northwind Incorporated Distributor of food and beverage products Customers: Restaurants and specialty food stores Suppliers: Come from around the world In the lab and lectures, you will see how efficiently a database management system can provide rich information to the organization.

C. Steps of Database Design What kinds of “things” does an organization want to collect information about? Determine the Entities For Northwind Inc, the “entities” of interest include: Customers Suppliers Employees Products Etc.

C. Steps of Database Design (cont.) 2. What specific information about each entity is important? Determine the attributes for each entity Example: For the Employee entity, attributes may include Employee name Address Hourly rate Etc. Who is this guy doing the interview? A “business analyst” For each employee, we keep track of … President of Northwind

C. Steps of Database Design (cont.) 3. How do we organize the data? Which type of database “model” shall we use? Assume: Use the most popular model  Relational model “Relation” refers to ??? Data is organized as a linked set of tables An example of a relational database management system that you are using in MIS 320 : ___________

Northwind Database in MS Access Sample Entity-Relationship Diagram (aka an “ERD” or “ER diagram”)

B. Database Questions (cont.) 4. What are the important aspects of a data table? Terminology for data tables Field (i.e. column) Attribute of the entity Record (i.e. row) An instance of an entity File (i.e., table) Collection of records for an entity Primary key Unique identifier for each record Often a unique “ID code” is created Example: See next figure Find all records in the Customer file for which the customer’s name field is Serena Lewis

Database Tables What are examples of a) Field, b) Record, c) File, and d) appropriate Primary Key ?? Supplier Table Supplier ID Company Name Street Address City State 1001 ACME Inc. 123 Easy St. Deming WA 1002 XYZ Corporation 456 Maple St. Bellingham 1003 ProductCo Inc. 389 Main St. Seattle … Product ID Product Name Unit Price ($) Supplier ID 800 Cheddar Cheese 15 1001 801 Swiss Cheese 12 802 Chuckanut Red Wine 20 1002 … …. Product Table

C. Steps of Database Design (cont.) 5. What are the relationships between the entities? A database involves tables that are linked together When building a database, we need to know how to link the tables i.e., We need to know how the entities are related! e.g., A Supplier provides a Product. If we know who the supplier is, we can find all the products they have supplied to us. For any product, we should be able to find the supplier’s address. Develop a “blueprint” diagram for database design Entity-relationship diagram

B. Database Questions (cont.) 5. What are the relationships between the entities? (cont.) Possible “relationship types” A) one to one, B) one to many, c) many to many “one” means “at most one” “many” means “more than one” Example: Entities: Supplier, Product What is the relationship type? We are told that: A supplier can provide many different kinds of products. A product can be supplied by a max of one supplier. Entity-Relationship Diagram: one ??? many ??? Supplier Product Provides

B. Database Questions (cont.) 5. Relationship symbols: these all mean the same thing The textbook used “crowsfoot” symbols Access uses “1 – ∞” symbols Access uses “ – ∞” symbols One Many Ignore these “inner” symbols

B. Database Questions (cont.) Foreign key Serves as a “link” between data files/tables A field in one file/table that serves as a primary key in another file/table How to determine the foreign key? For a “one to many” relationship, the primary key on the “one” side of the relationship is added to the table on the “many” side See examples

Database Tables: Northwest Inc. Supplier Table Supplier ID Company Name Street Address City State 1001 ACME Inc. 123 Easy St. Deming WA 1002 XYZ Corporation 456 Maple St. Bellingham 1003 ProductCo Inc. 389 Main St. Seattle … Product Table Product ID Product Name Unit Price ($) Supplier ID Category ID 800 Cheddar Cheese 15 1001 10 801 Swiss Cheese 12 802 Chuckanut Red Wine 20 1002 … …. Category ID Category Name Description 10 Dairy Cheese and milk products 20 Spirits Wine and liquors … Category Table

Northwind Database in MS Access: Primary/Foreign Keys Where are the primary keys? The foreign keys?

C. Steps of Database Design (cont.) 6. What do we do with the entity-relationship diagram? (cont.) ERD can be reviewed with client (Is the design correct for the client’s needs?) Database design can be used to build the database e.g., Build database in MS Access Can database design get more complicated than this? Yes! But … the previous example will suffice for MIS 320 The lab database projects will typically focus on “one to many” types of relationships

Terminology Summary The terms in each row have very similar meanings. For this course, learn all of the terms, but do not be concerned about the nuanced differences between terms in the same row. Easy to understand Academic Table (File) Entity / Relation Column Field Attribute Row Record Instance