Relational Database Fundamentals
- database maintains information about various type of object (inventory), events (transactions), people (employees), and places (ware-house).
- In hierarchical database model, 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
- 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
- entity in the relational database model is a person,place,thing,transaction, or events about which information is stored.
- attributes also called fields or columns , are characteristics or properties of an entity class.
- a primary key is a fields (or group of fields) that uniquely identifies a given entity in the table.
- a 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
Increased Flexibility
- database tends to mirror business structures, and a good database can handle changes quickly and easily, just as any good business need to be able to handle changes quickly and easily
- the physical view of information deals with the physical storage of information on a storage device such as hard disk.
- logical view of information focuses on how users logically access information to meet their particular business needs.
Increased scalability and performance
- scalability refers to how well system can adapt to increased demands.
- performance measure how quickly 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 location.
Increased information integrity (quality)
- information integrity is a measure of the quality of information.
- integrity constraints are rules that help ensure the quality of information.
- relational integrity constraints are rules that enforces basic and fundamental information-based constraints.
- business-critical integrity constraints enforce business rules vital to an organization's success and often require more insight and knowledge than relational integrity constraints.
- DBMS is software through which users and application programs interact with a database.
data driven websites
- data driven websites is an interactive website kept constantly update and relevant to the needs of its customers through the use of a database.
integrating information among multiple databases
- integration allows separate system to communicate directly with each other.
- forward integration takes information entered into a given system and send it automatically to all downstream systems and processes.
- a backward integration takes information entered into a given system and send it automatically to upstream system and process.