3_Lecture_Notes

# 3_Lecture_Notes - MIS 380 CLASS 3 What We Are Covering...

This preview shows pages 1–6. Sign up to view the full content.

1 CLASS # 3 MIS 380 Quiz 1 – Readings 1 & 2, Relational Model, PKs Normalization Step 1: Create an un-normalized relation Step 2: Separate repeating & non-repeating attributes Step 3: Remove partial dependencies Step 4: Remove transitive dependencies Normal forms (1NF, 2NF, and 3NF) Normalizing additional forms Step 5: Merge relations Using Normalization to Check ERDs Assignment 2 – Patient Database Normalization What We Are Covering Today

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

View Full Document
2 CLASS # 3 MIS 380 NORMALIZATION IN THE RELATIONAL MODEL WE NEED TABLES THAT ALLOW US TO : INTERRELATE DATA MAINTAIN DATA CONSISTENCY MINIMIZE REDUNDANCY THE NORMALIZATION PROCESS CAN BE USED TO CONVERT EXISTING FORMS AND REPORTS INTO A RELATIONAL MODEL FOR A DATABASE ALSO USEFUL FOR CHECKING THE CONVERSION PROCESS OF GOING FROM AN ERD TO RELATIONAL TABLES GOAL: THIRD NORMAL FORM (3NF) - EACH NON-KEY COLUMN DEPENDS ON THE KEY, THE WHOLE KEY, AND NOTHING BUT THE KEY
3 CLASS # 3 MIS 380 ACME CORPORATION 125 MAIN ST. CUSTOMER ORDER FORM ORDER: 1234 CUSTOMER: H36475 DATE: 01/01/90 NAME: FRED JONES SALESPERSON: 123 CODE DESCRIPTION PRICE QNTY X-234 RADIO 29.95 2 X-334 RADIO 39.95 1 G-484 TELEPHONE 59.00 1 R-586 CLOCK 15.25 3 NORMALIZATION BEGINS BY TAKING A FORM OR REPORT REPRESENTING DATA THE COMPANY WANTS TO STORE

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

View Full Document
4 CLASS # 3 MIS 380 STEP 1 - CREATE AN UN-NORMALIZED RELATION DETERMINE ATTRIBUTES CHOOSE AND UNDERLINE PRIMARY KEY INDICATE ANY REPEATING ATTRIBUTES UN-NORMALIZED RELATION OrderId CustomerId OrderDate CustomerName SalesPersonId ProductCode Description Price Quantity REPEATING O# C# DATE NAME SMAN P# DESC PRICE QUAN 1234 X X X X X X X X X X X X X X X X 1235 X X X X X X X X X X X X NOTE THAT THIS TABLE IS NOT A VALID RELATION SINCE SOME OF THE CELLS WOULD CONTAIN MORE THAN ONE PIECE OF DATA RELATED ATTRIBUTES THAT CAN HAVE MULTIPLE VALUES IN A SINGLE ROW ACME CORPORATION 125 MAIN ST. CUSTOMER ORDER FORM ORDER: 1234 CUSTOMER: H36475 DATE: 01/01/90 NAME: FRED JONES SALESPERSON: 123 CODE DESCRIPTION PRICE QNTY X-234 RADIO 29.95 2 X-334 RADIO 39.95 1 G-484 TELEPHONE 59.00 1 R-586 CLOCK 15.25 3 Not Attributes Primary Key
5 CLASS # 3 MIS 380 THINK ABOUT IT UN-NORMALIZED RELATION OrderId CustomerId OrderDate CustomerName SalesPersonId ProductCode Description Price Quantity REPEATING The mixing of repeating and non-repeating items on the same form is an indication that there are at least two different entities represented on the form – one for the repeating items and one for the non-repeating Here we have an order entity represented by the non-repeating items and a product entity represented by the repeating items. What is the relationship between orders and products? The form shows directly that a single order contains many products. But on how many orders can a particular product appear? This form shows just one order but there will be many such forms and across those various orders a particular product can appear on many orders.

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

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 01/24/2011 for the course FIA 111 taught by Professor Matta during the Spring '10 term at Hocking.

### Page1 / 30

3_Lecture_Notes - MIS 380 CLASS 3 What We Are Covering...

This preview shows document pages 1 - 6. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online