Valuing and Storing Information, Intro to ER Diagrams

1. Increased Flexibility

   Nota:

   • One Physical view but can have multiple logical views
   1. PHYSICAL VIEW

      Nota:

      • The physical storage of information on a storage device like a hard drive
   2. LOGICAL VIEW

      Nota:

      • How users logically access their information to meet their business needs; You can use the info differently and thereby have multiple logical views
      1. RELATIONAL INTEGRITY CONSTRAINTS
         1. BUSINESS-CRITICAL INTEGRITY CONSTRAINTS

            Nota:

            • 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
            1. DBMS DATA BASE MANAGEMENT SYSTEM

               Nota:

               • A software through which users and applications interact with a database
               1. INTEGRATION

                  Nota:

                  • 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
                  1. FORWARD vs BACKWARD INTEGRATION

                     Nota:

                     • Takes info and sends it automatically to all downstream systems and processes; vice versa
               2. USER CAN INTERACT
                  1. DIRECTLY
                  2. INDIRECTLY
            2. VS

               Nota:

               • Businesses that use constraints usually see fewer information errors and more use of organizational information
   3. Increased Scalability and Performance

      Nota:

      • Scalability is how well a system can adapt to different demands How quickly a system performs a certain process or transaction
      1. Reduced Information and Redundancy
         1. Increased Information Integrity
            1. Increased Information Security
            2. RELATIONAL INTEGRITY CONSTRAINTS

               Nota:

               • 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
2. RELATIONAL DATABASE

   Nota:

   • A database the stores information in the form of logically related two-dimensional tables

Nota:

• extent of DETAIL within the information

1. TRANSACTIONAL INFO

   Nota:

   • day to day operations-sales, purchases, updates
   1. ANALYTICAL INFO

      Nota:

      • take some sort of transactional data and summarize it to make decisions
      1. REAL-TIME IS

         Nota:

         • Immediate, up-to-date information per query requests
         1. 5 MEASURES OF INFO QUALITY
            1. ACCURACY

               Nota:

               • Are all values correct? Name spelling, dollar amount recorded properly
            2. COMPLETENESS

               Nota:

               • Are any values missing? Is address complete?
            3. CONSISTENCY

               Nota:

               • Is aggregate or summary info in agreement with detailed info?
            4. UNIQUENESS

               Nota:

               • Is each transaction, entity, an event only entered once in the info? Duplicate customers?
            5. TIMELINESS

               Nota:

               • Is the info current with respect to the business requirements? Is info update, weekly, monthly, etc?
            6. DATABASES
               1. 1. ENTITY

                     Nota:

                     • A table;
                     1. ATTRIBUTE

                        Nota:

                        • A column; A person, place, event, thing, transaction, or event about which information is stored
                        1. INSTANCE

                           Nota:

                           • ROWS of data
               2. PRIMARY KEY

                  Nota:

                  • A field or group of fields that uniquely identifies an attribute
                  1. FOREIGN KEY

                     Nota:

                     • A primary key in one table that appears as an attribute in another table; Acts to provide a logical relationship between tables
            7. ACCUT