Simple Solutions to Complex Problems
  • Simple Solutions
    • Documents Live Once
    • Good JIgs
    • Polya and Friends
  • Long Term Relations
    • Customers & Projects >
      • APU OverView >
        • APU Early Years
        • APU Middle Years
        • APU Late Years
      • AQMD >
        • DataGeneral v Hewlett Packard
      • Big Lots
      • The Federate Group >
        • Stabilizing the System
        • The Cash Register System
        • Later Projects
      • Munson Management Systems
      • National Electronics
      • Richey Electronics
      • Sierra Pacific Investments
      • Other Customers
  • Diagonal Method
    • D2-M2 >
      • Diagonal differs from Agile
      • Maintenance Projects
      • Manufacturing Projects
      • Research Projects
    • Data Structures >
      • Data Levels
      • Data Logging
      • Data Merging
      • Data Input Buffers
      • Data Sorting
      • Data Deltas
    • Readable Source Code >
      • Readable Code Modifications
      • Readable Paradigms
      • Readable Style
    • Critical Path Method >
      • CPM Data Tasks
      • CPM Menu and Security
      • CPM External Tasks
      • CPM: Early Calculations
      • CMP Stem to Stern >
        • Work Units
    • Semi-Interpretive Mindset >
      • Simple Semi-Interpretive Case Study 1
      • Semi-Interpretive Case Study 1 -- Semesters 2 and 3
      • More Thorough and Efficient
      • Software Research Northwest
    • Semi-Interpretive Methods
    • Concepts and Practices >
      • Data Changes
      • Data Stacks
      • Data Tokens and Loose Linking
    • Diagrams & Examples >
      • Venn Diagrams
      • Music Score as a Diagram
      • Cause & Effect Diagrams
    • Dictionary and Lexicon
  • Programmers
    • Tools and Languages >
      • python considerations
      • program names, like sa5comm
    • Perspectives of a Manager
    • ToDo
    • HTML testing
    • Private Thoughts
    • Leads
  • Contact Pilgrim
    • Land of the Free
    • Pilgrim Legal Status
    • Index to Pages
  • New Page
  • Stonehenge Simply Done
Picture
Picture
PO Levels
In this example of a data levels, the keys increase as the levels move downward.  (The example needs another date on the PO Receipts.) Even subsidiary records like po_receipts probably keeps the same keys, Simple set theory can resolve most questions about the data.
Class Levels
In past decades, some people wanted to denormalize such deep levels.  For example, within the table called classes, a large integer might represent the particular group of six keys from orgn thru clssn. With modern big disk drives, let the keys grow; with six levels, the composite key might be 30 to 50 bytes long.  The key from each upper layer continues down to the lower record. Good tracking of keys makes for logical processing. 
Logging adds another level below the enrollment records. 
PCC 1982 - 2014