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Data Modeling Basics. GENERAL PROGRESSION. DEVELOP BASIC MODEL ENHANCE BASIC MODEL REFINE THE MODEL VALIDATE THE MODEL. DATA ANALYSIS. "WHAT THERE IS“ WHAT INFORMATION IS REQUIRED BY THE BUSINESS. ACTIVITY ANALYSIS. "WHAT IS DONE“ WHAT ACTIVITIES MAKE UP THE BUSINESS. ENTITY TYPES.
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GENERAL PROGRESSION • DEVELOP BASIC MODEL • ENHANCE BASIC MODEL • REFINE THE MODEL • VALIDATE THE MODEL
DATA ANALYSIS "WHAT THERE IS“ • WHAT INFORMATION IS REQUIRED BY THE BUSINESS
ACTIVITY ANALYSIS "WHAT IS DONE“ • WHAT ACTIVITIES MAKE UP THE BUSINESS
ENTITY TYPES • TYPES OF THINGS THE BUSINESS NEEDS TO OPERATE • A COLLECTION OF OBJECTS WITH A COMMON DEFINITION AND LIKE CHARACTERISTICS • NAMES OF ENTITY TYPES ARE ALWAYS SINGULAR NOUNS: • EMPLOYEE • PRODUCT • SHIPMENT • CUSTOMER LOCATION • CAR
ENTITY • AN ENTITY IS A FUNDAMENTAL THING OF RELEVANCE TO THE ENTERPRISE ABOUT WHICH DATA MAY BE KEPT • AN ENTITY IS A SINGLE OCCURRENCE OF AN ENTITY TYPE • ENTITY TYPE: • EMPLOYEE • ENTITY: • MARY JOHNSON • JACK ALLEN • GENE SMITH
RELATIONSHIPS • ASSOCIATIONS BETWEEN ENTITY TYPES • A REASON OF RELEVANCE TO THE ENTERPRISE FOR ASSOCIATING ENTITIES FROM ONE OR TWO ENTITY TYPES • ENTITY TYPE #1: EMPLOYEE • ENTITY TYPE #2: FACTORY • RELATIONSHIP: works in • EMPLOYEE works in FACTORY • FACTORY receives work of EMPLOYEE
ATTRIBUTES • FACTS ABOUT ENTITIES THAT • ARE USEFUL TO THE BUSINESS • CHARACTERISTICS OF AN ENTITY TYPE THAT ARE IMPORTANT TO THE BUSINESS • ENTITY TYPE: EMPLOYEE • ATTRIBUTES: • NAME • ADDRESS • BIRTHDATE • SERVICE DATE • SALARY
ELEMENTS OF AN ERD (ENTITY RELATIONSHIP DIAGRAM) • ENTITY TYPE • RELATIONSHIPS • ATTRIBUTE
ELEMENTS OF AN ERD • ENTITY TYPE • A FUNDAMENTAL THING OF RELEVANCE TO THE ENTERPRISE ABOUT WHICH FACTS CAN BE KEPT AND WHICH IS INVOLVED IN RELATIONSHIPS WITH OTHER ENTITY TYPES. • RELATIONSHIPS • AN ASSOCIATION OF INTEREST BETWEEN ENTITY TYPES; THE RATIONALE FOR ASSOCIATING ENTITIES OF DIFFERENT TYPES. • ATTRIBUTE • A CHARACTERISTIC OF AN ENTITY TYPE. INDIVIDUAL DETAILS ASSIGNED TO EACH ENTITY.
ENTITY TYPES NAMES • USER SUPPLIES TO ANALYST • USER TERMS • CLEAR AND CONCISE • DO NOT ABBREVIATE • SINGULAR • UNIQUE • ALIAS
FINDING ENTITY TYPES • INTERVIEWS • BUSINESS DOCUMENTS • FILES
RELATIONSHIP • AN ASSOCIATION BETWEEN ENTITY TYPES ENTITY _____ BUSINESS ______ ENTITY TYPE REASON TYPE PATRON -------- RENTS -------- TAPE