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1、Data MODELING AND Analysis,What Is Data Modeling?,Data modeling is a technique for organizing and documenting a systems data. Data modeling is sometimes called database modeling because a data model is usually implemented as a database.,System Concepts For Data Modeling, Entitiesa class of persons,p
2、laces,objects,events,or concepts about which we need to capture and store data. Attributesa descriptive property or characteristic of an entity.Synonyms include element,property,and field. Relationshipsa natural business association between one one or more entities.,Relationships, nonidentifying rel
3、ationshia relationship in which each participating entity has its owm independent primary key. identifying relationship a relationship in which the parent entitys key is also part of the primary key of the child entity. nonspecific relationship a relationship where many instances of an entity are as
4、sociated with many instances of another entity.Also called many-to-many relationship.,The Process Of Logical Data Modeling,Strategic Data Modeling Data Modeling during Systems Analysis Looking Ahead to Systems Design Automated Tools for Data Modeling,How to Construct Data Models,Entity Discovery The
5、 Context Data Model The Key-Based Data Model Generalized Hierarchies The Fully Attributed Data Model,Analyzing the Data Model, What is a Good Data Model?1. A good data model is simple.2. A good data model is essentially nonredundant.3. A good data model should be flexible andadaptable to future need
6、s. Data Analysisa technique used to improve a data model forimplementation as a database. Normalization Examplea data analysis technique that organizes data into groups to form nonredundant,stable,flexible,and adaptive entities.,Normalization, first normal form(1NF)an entity whose attributes have no
7、 more than one value for a single instance of that entity. second normal form(2NF)an entity whose non-primary-key attributes are dependent on the full primary key. third normal form(3NF)an entity whose non-primary-key attributes are not dependent on any other non-primary-key attributes.,Mapping Data Requirements to Locations,data-to-location-CRUD matrixa matrix that is used to map data requirements to locations.,
