Database is an organized collection of data. Database Management System (DBMS) is a group of programs that manipulate the database. Besides that, it is also provide an interface between the database and its users and other application programs.
Without data and the ability to process the data, an organization could not successfully complete most business activities. Data consists of raw facts. To transform data into useful information, it must first be organized in a meaningful way.
Hierarchy of Data
Data Warehouses, Data Marts, and Data Mining
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- Bit - a binary digit
- Byte - typically made up of eight bits
- Character - basic building block of information
- Field - name, number, or combination of characters that describes an aspect of a business object or activity
- Record - collection of related data fields
- File - collection of related records
- Database - collection of integrated and related files
Data Entities, Attributes and Keys.
Entity - general class of people, places, or things(objects) for which data is collected, stored and maintained.
Attribute - characteristics of an entity
Data Item - specific value of an attribute
Keys - field or set of fields in a record that is used to identify the record
Primary key - field or set of fields that uniquely identifies the record
The Database Approach
- Traditional approach to data management: - Each distinct operational system used data files dedicated to that system
- Database approach to data management: - Pool of related data is shared by multiple application programs
The Relational Database Model
The relational model describes data using a standard tabular format. Each row of a table represents a data entity or record. The columns of the table represent attributes or fields.
Relational database model also about manipulating data with some process which are:
- Selecting - Eliminates rows according to certain criteria
- Projecting - Eliminates columns in a table
- Joining - Combines two or more tables
- Linking - Manipulating two or more tables that share at least one common data attribute
Database Management Systems (DBMS)
DBMS is about crating and implementing the right database system which ensure that the database will support both business activities and goals.
- Data warehouse : Database that holds business information from many sources in the enterprise
- Data mart : Subset of a data warehouse
- Data mining : Information-analysis tool that involves the automated discovery of patterns and relationships in a data warehouse
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