380%20Sum11%20Cl8%20Model%20to%20tables%20HO%20corrected%2020

380%20Sum11%20Cl8%20Model%20to%20tables%20HO%20corrected%2020

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon
380 Class 8 - Models to Tables REA models to tables Ch.9,10 » Mr. Video » Bowerkate practice
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Muddiest Points
Background image of page 2
Steps to convert REA models to  3NF tables 1. Create a table for every entity a. Assign a Primary Key to every table 1. For many-to-many (N:N) max rel’ns – create an additional (new) table whose PKey is a composite of the PKeys from the two tables involved in the N:N. For relationships with a minimum of 1: 1. For one-to-one (1,1)-(1,1) relationships – put both entities’ attributes in a single table. 2. If (1,1) on one side of relationship, put its PKey as Fkey into other table (usually max=N).
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Convert ER models to 3NF tables  (not in text) For remaining relationships look closely at 0s (0,1)-(0,1); (0,1)-(1,1); (0,1)-(0,N); (0,1)-(1,N) 1. A) If 98% of time there is/will be a value (i.e. practical min 1) call ‘ High load ’, treat min=0 as if min=1, and do step 4 (few blank cells created). **BUT in Access, See #6** B) If 50% or less of time there is a value (i.e.
Background image of page 4
Image of page 5
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 08/07/2011 for the course ACC 380 taught by Professor Harkness during the Spring '11 term at University of Michigan-Dearborn.

Page1 / 15

380%20Sum11%20Cl8%20Model%20to%20tables%20HO%20corrected%2020

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online