Chapter 7 : Storing Organizational Information - Databases

RELATIONAL DATABASE FUNDAMENTALS

• Information is everywhere in an organization.
• Information is stored in databases.
• Database – maintains information about various types of objects (inventory), events (transactions), people (employees) and places (warehouses).
• 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.

ENTITIES & ATTRIBUTES

• Entity – a person, place, thing, transaction or event about which information is stored.
• Attributes (fields, columns) – characteristics or properties of an entity class.

KEYS & RELATIONSHIPS

• Primary keys and foreign keys identify the various entity classes (tables) in the database.

1. Primary key – a field (or group of fields) that uniquely identifies a given entity in a table.
2. Foreign key – a primary key of one table that appears an attribute in another table and acts to provide a logical relationship among the two tables.

RELATIONAL DATABASE ADVANTAGES

• Database advantages from a business perspective include :

1. Increased flexibility
2. Increased scalability and performance
3. Reduced information redundancy
4. Increased information integrity (quality)
5. Increased information security

1. Increased flexibility

• A well-designed database should :

1. Handle changes quickly and easily.
2. Provide users with different views.
3. Have only one physical view. Physical view – deals with the physical storage of information on a storage device.
4. Have multiple logical views. Logical view – focuses on how users logically access information.

2. Increased scalability and performance

• A database must scale to meet increased demand, while maintaining acceptable performance levels.
• Scalability – refers to how well a system can adapt to increased demands.
• Performance – measures how quickly a system performs a certain process or transaction.

3. Reduced information redundancy

• Databases reduce 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.

4. Increased information integrity (quality)

• Information integrity – measures the quality of information.
• Integrity constraint – rules that help ensure the quality of information :

1. Relational integrity constraint
2. Business-critical integrity constraint

5. Increased Information Security

• Information is an organizational asset and must be protected.
• Databases offer several security features including :

1. Password – provides authentication of the user.
2. Access level – determines who has access to the different types of information.
3. Access control – determines types of user access, such as read-only access.

DATABASE MANAGEMENT SYSTEMS

• software through which users and application programs interact with a database.

DATA DRIVEN WEBSITES

• an interactive website kept constantly updated and relevant to the needs of its customers through the use of a database.

DATA DRIVEN BUSINESS INTELLIGENCE

• business intelligence in a data-driven website

INTEGRATING INFORMATION AMONG MULTIPLE DATABASES

• Integration – allows separate systems to communicate directly with each other.

1. Forward integration – takes information entered into a given system and sends it automatically to all downstream systems and processes.
2. Backward integration – takes information entered into a given system and sends it automatically to all upstream systems and processes.

• Forward integration and backward integration

• Building a central repository specifically for integrated information