Entry

Database: Relational: Normalization: Simple: Algorithm: How to do normalization using BBCBASIC?

Dec 24th, 2003 16:59
Knud van Eeden,

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--- Knud van Eeden --- 25 December 2003 - 01:44 am -------------------

Database: Relational: Normalization: Simple: Algorithm: How to do 
normalization using BBCBASIC?

---

                            employee
                                |
            +-------------------+----------+
            |                              |
        jobhistory                       offspring
            |
       salaryhistory

---
---

Steps: Overview:

 1. -Store the given tree

 2. -Create an output

 2. -Run the algorithm

---
---

Steps: Worked out:

 1. -Store the given tree in an array

    INPUT
    --------------------------------------------------------
    1. employee#      | jobhistory    | offspring | -1     |
    --------------------------------------------------------
    2. jobhistory#    | salaryhistory | -1        |        |
    --------------------------------------------------------
    3. salaryhistory# | -1            |           |        |
    --------------------------------------------------------
    4. offspring#     | -1            |           |        |
    --------------------------------------------------------

     This is one of the easiest ways to store the tree.

     ---

     Each row contains a node,
     with on the right of it all its children,

     ---

     Followed by -1
     (to indicate that there are no more childs for that node)

     ---

     You indicate that that node has a key, by putting a '#' at the end
     of its name.

     ---

  2. -Create some output structure in an array

    OUTPUT
    --------------------------------------------------------
    1.
    --------------------------------------------------------
    2.
    --------------------------------------------------------
    3.
    --------------------------------------------------------
    4.
    --------------------------------------------------------

 3. -Store initially all keys in the output

    OUTPUT
    --------------------------------------------------------
    1. [employee#]
    --------------------------------------------------------
    2. [jobhistory#]
    --------------------------------------------------------
    3. [salaryhistory#]
    --------------------------------------------------------
    4. [offspring#]
    --------------------------------------------------------

 2. -Run the algorithm: in general

      1. Start with the current node equal to the root

          employee#

       ---

       1. For the current node

          employee#

        ---

        1. If the current node has no children anymore:

           1. Return

        ---

        1. For first to last child of that node

         1. Add all the keys of the current node to that child
            (e.g. put it in front)

             OUTPUT
             --------------------------------------------------------
             1. [employee#]
             --------------------------------------------------------
             2. employee# [jobhistory#]
             --------------------------------------------------------
             3. [salaryhistory#]
             --------------------------------------------------------
             4. employee# [offspring#]
             --------------------------------------------------------

        2. Next child

        ---

       3. Repeat the above steps for all the childs of the current node

       ---
       ---

       1. For the current node

          jobhistory

        ---

        1. If the current node has no children anymore:

           1. Return

        ---

        1. For first to last child of that node

         1. Add all the keys of the current node to that child
            (e.g. put it in front)

             OUTPUT
             --------------------------------------------------------
             1. [employee#]
             --------------------------------------------------------
             2. employee# [jobhistory#]
             --------------------------------------------------------
             3. employee# jobhistory# [salaryhistory#]
             --------------------------------------------------------
             4. employee# [offspring#]
             --------------------------------------------------------

        2. Next child

        ---

       3. Repeat the above steps for all the childs of the current node

       ---
       ---

       1. For the current node

           offspring

        ---

        1. If the current node has no children anymore:

           1. Return

        ---
        ---

       1. For the current node

          salaryhistory

        ---

        1. If the current node has no children anymore:

           1. Return


---
---

So the final result is:

 OUTPUT
 --------------------------------------------------------
 1. [employee#]
 --------------------------------------------------------
 2. employee# [jobhistory#]
 --------------------------------------------------------
 3. employee# jobhistory# [salaryhistory#]
 --------------------------------------------------------
 4. employee# [offspring#]
 --------------------------------------------------------

---
---

Internet: see also:

---

Database: Relational: Normalization: Simple: How to do normalization?
http://www.faqts.com/knowledge_base/view.phtml/aid/27720/fid/147

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