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Unformatted text preview: TABLES RELATIONSHIPS AMONG RECORDS Parts of a database MIS in Use 4-1 MIS
– Microsoft marketing promotion – New version of SQL Server can handle large New databases databases
Over 30 tables & over 3 terabytes of data Database Applications Database
Forms Reports Queries Forms Forms Reports Reports Queries Queries Queries (cont.) Queries
Used to find specified information from the Used database quickly database World Bank knowledgebase Microsoft knowledge portal Queries (cont.) Queries Queries (cont.) Queries Database Development Database Talk to users and get their requirements Data Model Data
Representation of database data
– A “blueprint” Entity-relationship (E-R) data model
– Describe content using a diagram of things Describe (entities) and the relationships among those and relationships entities entities Data model entities Data
Identifier Student Entity Attributes Identifier Adviser Entity Attributes Relationships Relationships Entity-Relationship (E-R) Diagrams Diagrams
1:N N:M MAXIMUM CARDINALITIES: 1:N = one to many; N:M = many to many E-R Diagrams (cont.) E-R
MINIMUM CARDINALITIES At least one of that entity required Optional – relationship doesn’t have to have an entity of that type Transforming the Data Model Transforming 1. Create table for each entity • Identifier becomes key • Attributes become columns 2. Show relationships Data model entities Data
Identifier becomes KEY Attributes become COLUMNS Create TABLE for Student Entity Identifier becomes KEY Attributes become COLUMNS Create TABLE for Adviser Entity Converting the ER diagram to tables with relationships Importance of User’s Review Importance
User review crucial because…
– Data model must reflect your view – Changes costly in terms of time and money Reflections: “Requirements Creep” Creep”
Vicious cycle - System adapted to add Vicious new features which create new uses which create new requirements which Group Exercise Group
Pick an existing company What info would they need in their What database? database?
– What tables? – What kind of relationships?
Primary keys and foreign keys Business Intelligence Business
INPUTS • Data from many different databases into larger stores of data (data warehouses & data marts) Transformation Process: Data Mining Analysis OUTPU...
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- Spring '08