- 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
- 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 :
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.
- 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
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