null
US
Sign In
Sign Up for Free
Sign Up
We have detected that Javascript is not enabled in your browser. The dynamic nature of our site means that Javascript must be enabled to function properly. Please read our
terms and conditions
for more information.
Next up
Copy and Edit
You need to log in to complete this action!
Register for Free
13410090
ICT OCR A Level - Distributed Databases
Description
Notes on distributed databases
No tags specified
databses
distributed databases
duplicated databases
partitioned
security.
it
a level
Mind Map by
Connor Graham
, updated more than 1 year ago
More
Less
Created by
Connor Graham
over 6 years ago
29
0
0
Resource summary
ICT OCR A Level - Distributed Databases
What are they?
A single logical databse
All parts are physically in different locations
Parts are accessible over a network.
A standard Database looks like:
A typical database looks like:
Each site has a Database Management System (DBMS)
Allows queries to be made locally
Also has a Distributed Database Management System
Allows queries to be made globally for the whole system
Why use them?
Examples of uses:
Travel company with branches across the globe
International car manufacturer
Supermarket stocks with multiple branches
Some companies may need information up to date all of the time
Access the data globally once a user has updated the files.
Distributed databases reduce the risk of losing work
Central database is updated overnight
Batch processing
If the network goes down, then work is not lost and employees can work as normal until the issues are fixed.
Mainly independant; if one branch goes down, the others aren't affected
Duplicated Databases
Local copy of each part of the entire database is kept at each location
Not very practical for a number of reasons.
Disadvantages.
Very heavy use of the network
Whole database may be large and require a lot of storage space
Difficult to keep all copies up to date simultaneously
Does not scale well if the company grows
Wasteful if only certain parts are needed at certain branches
Advantage
More practical if the company is fairly small
Partitioned Databases
Database is 'split' or partitioned into different datasets depending on the specific needs of the organisation
Advantages
Each data store is independant
Network load is much less
Higher performance since there is no network bottleneck
Easier to solve problems due to each store being independant
Scales up very easily
Disadvantages
May not be the best solution if each branch needs constant updates of data
Needs to be carefully partitioned to keep each section as local as possible
Partitioned+Index
A modification of the partitioned database is to include an index of all remote database records as well
Each store has an index pointing to all records in the entire database
Advantages
Still a high performance as most queries remain local
Can efficiently access remote records by using the index
Disadvantages
System must keep all indexes up to date
More complicated to create and manage
Overall
Security
Multiple entry points, this can make the database less secure. Each 'node' needs to be kept secure
Data encryption keys are more likely to be intercepted if they are spread around the organisation constantly
If one node is hacked then the rest of the organisation is vulnerable as well
Advantages
Resilient, if one part of the database stops working, there rest are not affected
Security: each employee is able to access one portion of the data
Network traffic is minimised so there is less bandwidth expenses
Easier to keep any errors local
High performance due to less network bottleneck
Disadvantages
More complex to create and maintain
Many entry points to the whole database is less secure
Data integrity is harder to maintain to ensure the indexes are not corrupted
Not as effective if there is heavy interaction between branches
Media attachments
Typical Database (binary/octet-stream)
Distributed Database (binary/octet-stream)
Distributed Database (binary/octet-stream)
Show full summary
Hide full summary
Want to create your own
Mind Maps
for
free
with GoConqr?
Learn more
.
Similar
Common Technology Terms
Julio Aldine Branch-HCPL
Project Communications Management
farzanajeffri
Network Protocols
Shannon Anderson-Rush
Abstraction
Shannon Anderson-Rush
Computing
Kwame Oteng-Adusei
HTTPS explained with Carrier Pigeons
Shannon Anderson-Rush
Introduction to the Internet
Shannon Anderson-Rush
Construcción de software
CRHISTIAN SUAREZ
Historical Development of Computer Languages
Shannon Anderson-Rush
Useful String Methods
Shannon Anderson-Rush
Web Designing & Development Full Tutorial
Nandkishor Dhekane
Browse Library