chapter 7: Storing organizational information - Database.

Learning outcomes:
7.1. Define the fundamental concepts of the relational database model.
7.2. Evaluate the advantages of the relational database model.
7.3. Compare relational integrity constraints and business-critical integrity constraints.
7.4. Describe the benefits of a data driven website.
7.5. Describe the two primary methods for integrating information across multiple databases.

Relational database fundamentals

• The core component of any system, regardless of size, is a database and a database management systems.
• Database maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouse).
• A Database Management System (DBMS) creates, reads, updates, and deletes data in a database while controlling access and security.
• For example, managers send requests to the DBMS, and the DBMS performs the actual manipulation of the data in the data-base.
• There are two primary tools available for retrieving information from a DBMS.
• First is a Query-by-example (QBE) - helps users graphically design the answer to a question against a database.
•  Second is Structured Query Language (SQL) - asks users to write lines of code to answer questions against a database.
• A data element (data field) is the smallest or basic unit of information such as customer's name, address, email and so on.
• Data models are logical data structures that detail the relationships among data elements using graphics or pictures.
• Metadata provides details about data. For example, metadata for image could include its size, resolution, and date created.
• Data dictionary compiles all of the metadata about the data elements in the data models.

DBMS use three primary models for organizing information which are :

• - 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.

• - Network Database Model

- A flexible way of representing objects and their relationships.

• - Relational Database Model.

- Stores information in the form of logically related two-dimensional tables.
- meaning that it can create a logical related information from one table to another table.

Hierarchical database model

 

 

Network Database Model

 

Relational Database Model

 

Entities and Attributes,

• Entity
• - a person, place, thing, transaction, or event about which information is stored.
• - The rows in each table contain the entities.
• Attributes (fields, column)
• - Characteristics or properties of an entity class.
• - the columns in each table contain the attributes.

Keys and Relationships
- Primary keys and Foreign Keys identify the various entity classes ( tables) in the database.

• Primary Key - A field (or group of fields) that uniquely identifies a given entity in a table.
• Foreign Key - A primary key of one table that appears again as an attributes in another table and acts to provide a logical relationship among the two tables.

Relational Database Advantages.
- Database advantages from a business perspective include:-

• Increased flexibility
• Increased scalability and performance
• Reduced information redundancy
• Increased information integrity (quality)
• increased information security.

Increased flexibility

• A well-designed database should handle changes quickly and easily.
• it also have to provide users with a different views. meaning that, database need to provide flexibility in allowing each users to access information in whatever ways best suits his or her needs.
• A database have only one physical view and multiple logical view.
• Physical view of information deals with the physical storage of information on a storage device.
• The logical view of information focuses on how individual users logically access information to meet their own particular business needs.

Increased scalability and performance.

• The database had to be scalable to handle the massive volumes of information and the large numbers of users expected for the launch of the website.
• The database also need to perform quickly under heavy use.
• A database must scale to meet increased demand, while maintaining acceptable performance levels.
• meaning that there will be no limitation to add on new information or to erase all the information.
• Scalability - refers to how well a system can adapt to increased demands.
• Performance - measures how quickly a system performs a certain process or transaction.

Reduced information Redundancy

•  Database can reduce information redundancy.
• Information redundancy is the duplication of data, or the storage of the same data/information in a multiple places.
• Redundant data can caused storage issues along with data integrity issues, making it difficult to determine which values are the most current or most accurate. This can lead to employees felt confused and frustrated when they are dealing with it.
• One primary goal of a database is to eliminate information redundancy by recording each piece of information in only one place in the database.
• this will save the disk space.
• Inconsistency is one of the primary problems with redundant information.

Increased information integrity (quality)

• Information integrity is a measures of the quality of information.
• Integrity constraints are rules that help ensure the quality of information.
• The database and DBMS ensures that users can never violate these constraints.
• There are two types of integrity constraints which are relational and business critical.

- Relational Integrity Constraints
- rules that enforce basic and fundamental information-based constraints.
- For example, a relational integrity constraints would not allow someone to create an order for non-existent customer or order zero pound of raw materials from the supplier.
- A business rule defines how a company performs certain aspects of its business and typically result in either yes/no or true/false answer.

- Business Critical Integrity Constraints.
- Rule that enforce business rules vital to an organization's success and often require more insight and knowledge than relational integrity constraints.
- For example, product return are not accepted for fresh product 15 days after purchase.
- Business critical integrity constraints tend to mirror the very rules by which an organization achieves success.
- The specification and enforcement of integrity constraints produce higher-quality information that will provide better support for business decisions.

Increased information security.

• Information is an organizational asset and must be protected.
• Databases offer several security features including :
• - Password - Provides authentication of the user.
• - Access level - Determines who has access to the different types of information.
• - Access control - Determines types of users access, such as read-only access.

Database Management System (DBMS)
- A software through which users and applications program interact with a database.
- this will protect the information or data of the organization or others department getting leaked easily.

 

Data-Driven Web Site

 

• A Content Creator is the person responsible for  creating the original website content.
• A Content Editor is the person responsible for updating and maintaining website content.
• Static Information includes fixed data incapable of change in the event of a users action.
• - A static information needs content editor to change it.
• - anything changes that happen in the website will change the database also and vice versa.
• Dynamic Information includes data that change based on users action.
• - For example, dynamic information changes when a user requests information and dynamic website changes when information based on user request such as movie ticket availability, airlines prices or restaurant reservation.
• Data-Driven Website is an interactive website kept constantly updated and relevant to the needs of its customers using a database.
• Data-driven website is a website that linked directly with the database.
• Data-driven website can help limit the amount of information displayed to customers based on unique search requirement.

There are a number of advantages to using the web access company databases which are:-

• Web browse are much easier to use than directly accessing the database using a custom-query tool.
• The web interface requires few or no changes to the database model.
• It costs less to add a web interface in front of a DBMS than to redesign and rebuild the system to support changes.

Data-driven Website business advantages are:

• Development - allows the website owner to make changes anytime - all without having to rely on a developer or knowing HTML programming.
• Content management - a statistic website requires a programmer to make updates. This adds an unnecessary layer between the business and its web content, which can lead to misunderstandings and slow turnarounds for desired changes.
• Future Expandability - having data-driven website enables the site to grow faster than would be possible with a static site. changing the layout, displays and functionality of the site (adding more features and sections) is easier with a data-driven solution.
• Minimizing Human Error - a well-design  data-driven website will have "error trapping" mechanisms to ensure that required information is filled out  correctly and that content is entered and displayed in tis correct format.
• Cutting Production and Update costs - a data-driven website can be updated and 'published' by any competent data entry or administrative person. In addition to being convenient and more affordable changes and updates will take a fraction of the time that they  would with static site.
• More efficient - with a data-driven solution, the system keep track of the templates, so users do not have to.
• Improved stability - with data-driven website, there is peace of mind, knowing the content is never lost - even if your programmer is.

Data-driven Business Intelligence.

 

BI in a data-driven website

 

Integrating Information among Multiple Database.

• Integration - allows separate system to communicate directly with each other.
• Forward integration - takes information entered into a given systems and sends it automatically to all downstream systems and processes.
•  Forward integration is a normal process.
• Backward integration - takes information entered into a given system and sends it automatically to all upstream systems and processes.
• Ideally, an organization wants to build both forward and backward integrations, which provide the flexibility to create, update and delete information in any of systems.
• However, integrations are expensive and difficult to build and maintain and most organization build only forward integration.

 

 

Integrating Information among Multiple database.

 

 

• The second integration method builds a central repository for a particular type of information.
• by using this multiple database integrating method organization can get consistence information even the redundancy cannot be eliminated all of it.
• Users also can create, update, and delete customer information only in the central customer information system.
• when users perform this task on the central customer information database, integration automatically send the new and/or update customer information to the other system.
• Without integration, an organization will:
• - spend considerate time entering the same info in multiple system.
• - suffer from the low quality and inconsistency typically embedded in redundant info.