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Chapter 7 : Storing Organizational Information

We are going to learn how and where all the information is stored. All the organizational information is stored in a database. But the information is stored based on the concept of database that has been collected. Mostly the information is a collection of records, or pieces of information. Typically, a given database has a structural description of the type of facts held in that database. This description called as a schema. The schema describes the objects that are represented in the database and the relationship among them.

RELATIONAL DATABASE FUNDAMENTALS

There are three models for organizing information in a database

1. hierarchical models
2. network models
3. relational database models

From the transactional and analytical information, everything will be stored in database but the information will be store into its type itself. For example, if the information that been store is about marketing, so it will be group in marketing information in database.

Definition:

1. Database: maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouses)

2. Hierarchical models: information is organized into a tree-like structure that allows repeating information using parent/child relationships in such a way that it cannot have too many relationships in such a way that it cannot have too many relationships. However, it cannot be used to relate to structures that exist in the real world.

3. Network database model: flexible way of representing objects and their relationships. It is where it likes a tree of record with each record having one parent record and many children. Network model allows each record to have multiple parent and child record, forming a lattice structure

4. Relational database model: types of database that more prevalent because stores information in the form of logically related two-dimensional tables. Good database can handle changes quickly and easily

ENTITIES AND ATTRIBUTES

ENTITIES: in the relational database model is a person, place, thing, transaction, or event about which information is stored. A table in the relational database model is a collection of similar entities.

ATTRIBUTES: is called fields or columns, are characteristics or properties of an entity class. The columns in each table contain the attributes

KEYS AND RELATIONSHIPS

To manage and organize various entity classes within the relational database model, developers must identify primary keys and foreign keys and use them to create logical relationships.

Primary keys: a field (or group of fields) that uniquely identifies a given entity in a table. It is important because they provide a way of distinguishing each entity in a table.
Foreign key: in the relational database model is a primary key of one table that appears as an attribute in another table and acts to provide a logical relationship between the two tables.

RELATIONAL DATABASE ADVANTAGES:

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

i. INCREASE FLEXIBILITY :

· A well-designed database should handle changes quickly and easily, provide users with different views and have only one physical view

· The distinction between logical and physical view is very important in understanding flexible database user views.

a. Physical view: it deal with the physical storage of information on a storage device such as a hard disk.

b. Logical view: focuses on how users logically access information to meet their particular business needs.

ii. INCREASED SCALABILITY AND PERFORMANCE

· A database must scale to meet increased demand, while maintaining acceptable performance levels

· Scalability: how well a system can adapt to increased demands

· Performance: measure how quickly a system can adapt to increased demands

iii. REDUCED INFORMATION REDUNDANCY

· Redundancy: the duplication of information or storing the same information in multiple places.

· Inconsistency is one of the primary problems with redundant information.

· Goal of database is to eliminate redundancy by put the information in one place in the database. Thus it can save space, perform the information easier and improve the quality.

iv. INCREASED INFORMATION INTEGRITY (QUALITY)

· Information integrity: measures the quality of information

· Integrity constraint: rules that help ensure the quality of information and built into a database design. It can be divided into two types:-

a. Relational integrity constraint: rules that enforce basic and fundamental information based constraint.

b. Business-critical integrity constraint: enforce business rules vital to an organization’s success and often require more insight and knowledge than relational integrity constraint.

v. INCREASED INFORMATION SECURITY

· Information is an organizational asset and must be protected

· Databases offer several security features including:

a) Password: provides authentication of the user who is gaining and access to the system

b) Access level: determines who has access to the different types of information

c) Access control: determines types of user access, such as read-only access

DATABASE MANAGEMENT SYSTEMS

A database management system (DBMS) is software through which users and application programs interact with a database. It is where, the users send requests to the DBMS and the DBMS performs the actual manipulation of the information in the database. It can interact with two ways; directly or indirectly. DBMS is software for the users to access for communicate to get the information in database.