CHAPTER 7: STORING ORGANIZATIONAL INFORMATION - DATABASE

Database --->  maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouse).

Database models --->

• Hierarchical database model - information is organized into a tree-like structure (using parent/child relationship) in such a way that it cannot have too many relationship.
• 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.

Entities and Attributes --->

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

Keys and Relationship --->

• 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 an attribute in another table and acts to provide a logical relationship among the two tables.

Relational Database Advantages --->

• Increased flexibility - a well-designed database should handle changes quickly and easily and provide users with different view.
• Increased scalability performance - scalability refers to how well a system can adapt to increase demands. And performance is to 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.
•  Increased information integrity (quality) - information integrity is to measures the quality of information. And the integrity constraint is the rules that help ensure the quality of information. > relational integrity constraint and business-critical integrity constraint.
•  Increased information security - password provides authentication of the user,access level determines who has access to the different types of information, andaccess 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.

Database-Driven Websites ---> 

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

Integrating Information among Multiple Databases --->

• Integration is allows separate systems to communicate directly with each other. there has two ways is -forwards integration is takes information entered into a given system and sends it automatically to all downstream systems and processes. then, backward integration is takes information entered into a given system and sends it automatically to all upstream systems and processes.