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Base de données, Tables, Vues, Index et syntaxe SQL
Titre:
Help on data normalization, please
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Hello,
In the past I have broken data normalization rules but I am swearing that off :) I also want some table columns to be defined in a data driven way.
I'm asking for help to see if I am missing something important. Please give me your comments and criticism as I need to make a choice soon and don't want to make a bad one.
Say you have the following tables:
1. Header Table
header_id, other fields
2. Child Table
child_id, header_id, other fields
3. Table with name and value of "virtual fields" of child table - One record for each virtual column that has a non default value
Virtual_id, child_id, ColumnName, ColumnValue
4. Data dictionary with name of all possible "virtual fields" of child table - Contains description of all possible virtual columns
ColumnName,ColumnType,ColumnWidth,ColumnPrecision
I am considering the following approach to integrate data from tables 2 and 3 during user edits:
I use Codemine framework which makes it relatively easy to go the cursor approach.
- Create either an object or a cursor with the following properties / fields
child_id, header_id, other fields from child table, VirtualColumn1, VirtualColumn2, VirtualColumn3 etc
- Update base tables as user makes changes
All comments highly appreciated.
Alex
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