Valuing and Storing Information, Intro to ER Diagrams

Valuing and Storing Information, Intro to ER Diagrams

1. CONCEPTS

   • Fundamental concepts and benefits of the relational database model
     • Increased Flexibility
       • One Physical view but can have multiple logical views
       • PHYSICAL VIEW
         • The physical storage of information on a storage device like a hard drive
       • LOGICAL VIEW
         • How users logically access their information to meet their business needs; You can use the info differently and thereby have multiple logical views
         • RELATIONAL INTEGRITY CONSTRAINTS
           • BUSINESS-CRITICAL INTEGRITY CONSTRAINTS
             • Enforce business rules vital to an organizations success;  often requires more insight and knowledge than RI constraints Like a supplier of produce putting a return policy on produce that was delivered 15 days ago
             • DBMS DATA BASE MANAGEMENT SYSTEM
               • A software through which users and applications interact with a database
               • INTEGRATION
                 • Allows separate systems to communicate directly with each other-WITHOUT IT, an org will spend a lot of time inputting the data in multiple systems AND suffer with low quality or inconsistent data
                 • FORWARD vs BACKWARD INTEGRATION
                   • Takes info and sends it automatically to all downstream systems and processes; vice versa
               • USER CAN INTERACT
                 • DIRECTLY
                 • INDIRECTLY
             • VS
               • Businesses that use constraints usually see fewer information errors and more use of organizational information
       • Increased Scalability and Performance
         • Scalability is how well a system can adapt to different demands How quickly a system performs a certain process or transaction
         • Reduced Information and Redundancy
           • Increased Information Integrity
             • Increased Information Security
             • RELATIONAL INTEGRITY CONSTRAINTS
               • Rules that enforce basic and fundamental information based constraints i.e NOt allowing to buy 0 of one product, or place an order for a non-existent customer
     • RELATIONAL DATABASE
       • A database the stores information in the form of logically related two-dimensional tables

2. KEY TERMS

   • INFORMATION GRANULARITIES
     • extent of DETAIL within the information
     • TRANSACTIONAL INFO
       • day to day operations-sales, purchases, updates
       • ANALYTICAL INFO
         • take some sort of transactional data and summarize it to make decisions
         • REAL-TIME IS
           • Immediate, up-to-date information per query requests
           • 5 MEASURES OF INFO QUALITY
             • ACCURACY
               • Are all values correct? Name spelling, dollar amount recorded properly
             • COMPLETENESS
               • Are any values missing? Is address complete?
             • CONSISTENCY
               • Is aggregate or summary info in agreement with detailed info?
             • UNIQUENESS
               • Is each transaction, entity, an event only entered once in the info? Duplicate customers?
             • TIMELINESS
               • Is the info current with respect to the business requirements? Is info update, weekly, monthly, etc?
             • DATABASES
               • • ENTITY
                   • A table;
                   • ATTRIBUTE
                     • A column; A person, place, event, thing, transaction, or event about which information is stored
                     • INSTANCE
                       • ROWS of data
               • PRIMARY KEY
                 • A field or group of fields that uniquely identifies an attribute
                 • FOREIGN KEY
                   • A primary key in one table that appears as an attribute in another table; Acts to provide a logical relationship between tables
             • ACCUT

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