Solved

transitive dependency

Posted on 2003-11-11
1
2,256 Views
Last Modified: 2013-11-19
Im confused by what this is, arent they the same thing??
       
      
partial functional dependency
Description       
In database terminology, a partial functional dependency occurs when the value in a non-key attribute of a table is dependent on the value of some part of the table's primary key (but not all of it).

       
transitive dependency
Description       
A transitive dependency occurs in a database table when the value of a non-key attribute is dependent on the value of another non-key attribute in that table.

0
Comment
Question by:illucid
1 Comment
 
LVL 7

Accepted Solution

by:
yoren earned 125 total points
ID: 9729019
No. Here's an example with both a transitive dependency and a partial functional dependency. Key is SID/Major -- this student has a double major

SID      Major            School            Maj_GPA            School_Location
123      Physics            Engineering      4.0            EngTown
123      Music            Arts            3.3            Artsville

Transitive dependency: School *determines* School_Location (School is not a key)
Partial functional dependency: Major determines School (Major is part of the key)

Now, remove the partial functional dependency:

SID      Major            Maj_GPA      
123      Physics            4.0            
123      Music            3.3      

Major      School            School_Location
Physics      Engineering      EngTown
Music      Arts            Artsville


Still have a transitive dependency. Now remove that:


SID      Major            Maj_GPA            
123      Physics            4.0            
123      Music            3.3            

Major      School
Physics      Engineering
Music      Arts

School            School_Location
Engineering      EngTown
Arts            Artsville


...and you're in 3rd normal form.
0

Featured Post

PRTG Network Monitor: Intuitive Network Monitoring

Network Monitoring is essential to ensure that computer systems and network devices are running. Use PRTG to monitor LANs, servers, websites, applications and devices, bandwidth, virtual environments, remote systems, IoT, and many more. PRTG is easy to set up & use.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Checking the Alert Log in AWS RDS Oracle can be a pain through their user interface.  I made a script to download the Alert Log, look for errors, and email me the trace files.  In this article I'll describe what I did and share my script.
JavaScript has plenty of pieces of code people often just copy/paste from somewhere but never quite fully understand. Self-Executing functions are just one good example that I'll try to demystify here.
Via a live example, show how to restore a database from backup after a simulated disk failure using RMAN.
The viewer will the learn the benefit of plain text editors and code an HTML5 based template for use in further tutorials.

829 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question