Relation Database Fundamentals
- Information is everywhere in an organization.
- Information is stored in databases
- Databases - maintains information about various type of
objects (inventory), events (transactions), people (employees) and place
(warehouse)
Learning Outcomes
- Define the fundamental concepts of the relation database model.
- Evaluate the advantage of the relation database model.
- Compare relation integrity contraints and business-critical
integrity contraints.
Relation Database Fundamentals
- Database models include :
1. Hierarchical database model -
Information is organized into a tree-like structure (using parent/child
relationships) in such a way that it cannot have too many relationships.
2. Network database model - a
flexible way of representing objects and their relationships.
3. Relational database model -
stores information in the form of logically related two-dimensional tables.
RELATIONAL DATABASE FUNDAMENTALS
- A database maintains
information about various types of objects (inventory), events (transaction),
people (employees) and place (warehouses).
- Hierarchical database model is information is organized into tree-like structure that allows repeating information using parent/child relationships in such a way that it cannot have too many relationships.
- The network database model is a flexible way of representing objects and their relationships.
-The relational database model is a type of database that stores information in the form of logically related two-dimensional tables.
ENTITIES AND ATTRIBUTES
- A entity in the
relational database model is a person, place, thing, transaction or event about
which information is stored.
-Attributes called fields or
columns are characteristics or properties of an entity class
KEYS AND RELATIONSHIPS
-A primary key is a
field (group/fields) that uniquely identifies a given entity in a table.
-A foreign key is a primary key of one table that appears as an attributes in another table and acts to provide a logical relationships between the two tables.
RELATIONAL DATABASE ADVANTAGES
* Increased Flexibility
* Increased Scalability and Performance
* Reduced Information Redundancy
* Increased Information Integrity (Quality)
* Increased Information Security
Increased Flexibility
- Database provide flexibility in allowing each user to access the information in whatever way best suits his or her needs.
- The distinction between logical and physical
views is important in understanding flexible database user views.
-The physical views of
information deals with the physical storage of information on a storage
device such as a hard disk.
- The logical views of
information focuses on how users logically access information to meet
their particular business.
Increased Scalability and Performance
- Only a database could 'scale' to handle the massive volumes of information and the large numbers of users required for the successful launch of the Ellis Island website.
- Scalability refers to how
well a system can adapt to increased demand.
- Performance measures how
quickly a system performs a certain process or transaction.
Reduced Information Redundancy
- Redundancy is the duplication of information, or storing the same information in multiple places.
- Redundant information
occurs because organizations frequently capture and store the same
information in multiple locations.
- The primary problem with redundant information is
that it is often inconsistent which make it difficult to determine which
values are the most current or most accurate.
Increased Information Integrity (Quality)
- Information integrity is
a measures the quality of information
- Within a database environment, integrity
constraints are rules that help ensure the quality of
information. It can be defined and built into the database design.
- Two types of integrity constraints are :
· Relational
integrity constraints- rules that enforce basic and
fundamental information-based constraints
· Business-critical
integrity constraints- enforce business rules vital to an
organization's success and often require more insight and knowledge than
relational integrity constraints.
Increased Information Security
- Information is an organizational asset.
- Database offer many security features such as
* Passwords - provide authentication of the user
* Access levels - determines who has access to the different types of information
* Access control - determines types of user access such as customer service representatives might read-only access
- Database can increase personal security as well as information security.
DATABASE MANAGEMENT SYSTEMS
- A database management systems (DBMS) is software through which users and application programs interact with a database.
Data-Driven Websites
- A data-driven website is an interactive website keep constantly updated and relevant to the needs of its costumer through the use of a database.
Data-Driven Website Advantages
· Development :
Allows the website owner to make changes any time
· Content
management : A static website requires a programmer to
make updates.
· Future
expandability : Having a data-driven website enables the site to
grow faster than would be possible with a static site.
· Minimizing
human error
· More
efficient
· Improved
stability
INTEGRATING INFORMATION AMONG MULTIPLE DATABASE
- An integration allows separate systems to
communicate directly with each other.
- A forward integration takes information entered into a given system and sends it automatically to all downstream processes.
- A backward integration - takes information entered into a given systems and sends it automatically to all upstream systems and processes.
No comments:
Post a Comment