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Definitions Database: organized collection of logically related data Data: stored representations of meaningful objects and events Structured: numbers, text, dates Unstructured: images, video, documents Information: data processed to increase knowledge in the person using the data Metadata: data that describes the properties and context of user data Data in context Summarized data Disadvantages of File Processing Program-Data Dependence All programs maintain metadata for each file they use Duplication of Data Different systems/programs have separate copies of the same data Limited Data Sharing No centralized control of data Lengthy Development Times Programmers must design their own file formats Excessive Program Maintenance 80% of information systems budget Problems with Data Dependency 1) Each application programmer must maintain his/her own data 2) Each application program needs to include code for the metadata of each file 3) Each...

learn for free Database Data Modeling Documenting rules and policies of an organization that govern data. BUSINESS RULES Statements that define or constrain some aspect of the business. Examples: 1) Every student in the university must have one or more faculty advisers. 2) Every student in the university is assigned to one discipline only. Is this a business rule? A student is any person who has applied for admission or taken a course or training program from any credit or noncredit unit of the university A GOOD BUSINESS RULE IS: Declarative – what is required from system 1)Precise – Non-Ambiguous 2)Atomic – one statement 3)Consistent – does not contradict other rules 4)Expressible – structured, natural language 5)Distinct – non-redundant 6)Business-oriented – understood by business people CONCEPTUAL MODELING Entity-Relationship Model 1) A logical representation of data for an organization 2) Expressed in terms of entities, attributes and relationships Ent...