Normalization Summary, Checking for BCNF - Database Management - Lecture Slides, Summaries of Introduction to Database Management Systems

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Database

Management

System

Lecture - 21

Normalization Summary

A step by step process to make

DB design more efficient and

accurate

A strongly recommended activity

performed after the logical DB

design phase

Normalization Summary

Normalization forms exist up to

6NF, however, for most of the

situations 3NF is sufficient

Performed through Analysis or

Synthesis process

Normalization Example

Identify FDs

Apply on the relevant tables; see

if any normalization requirement

is being violated, that is, causing

some anomaly

Some Facts

2.Each project has one manager,

whose name is stored in PROJMGR

PROJNAME PROJMGR

1.Each project has a unique name,

but names of employees and

managers are not unique

3. Many employees may be assigned to work on each project, and an employee may be assigned to more than one project. HOURS tells the number of hours per week that a particular employee is assigned to work on a particular project

PROJNAME, EMPID HOURS

5. Salary gives the annual salary of an employee

EMPID SALARY

6. EMPMGR gives the name of the employee’s manager, who is not the same as the project manager

EMPID EMPMGR

8. RATING gives the employee’s rating for a particular project. The project manager assigns the rating at the end of the employee’s work on that project

PROJNAME, EMPID RATING

PROJNAME PROJMGR, BUDGET, STARTDATE

EMPID EMPNAME, SALARY, EMPMGR, EMPDEPT

EMPDEPT EMPMGR

PROJNAME, EMPID HOURS, RATING

PROJ ( PROJNAME, PROJMGR, BUDGET, STARTDATE)

EMP ( EMPID, EMPNAME, SALARY, EMPMGR, EMPDEPT)

WORK ( PROJNAME, EMPID, HOURS, RATING)

PROJ ( PROJNAME, PROJMGR, BUDGET, STARTDATE)

EMP ( EMPID, EMPNAME, SALARY, EMPDEPT)

DEPT ( EMPDEPT, EMPMGR)

WORK ( PROJNAME, EMPID, HOURS, RATING)

PROJ ( PROJNAME, PROJMGR, BUDGET, STARTDATE)

PROJNAME PROJMGR, BUDGET, STARTDATE

EMP ( EMPID, EMPNAME, SALARY, EMPDEPT)

EMPID EMPNAME, SALARY, EMPMGR, EMPDEPT