September 29th, 2016. Thursday.
Database - A collection of data organized in a manner that allows access, retrieval, and use of that data.
Data - A collection of unprocessed items. Such as text, numbers, images, audio, and video.
Information - Processed data. Examples: documents, audio, images, and video.
The database software, often also known as a database management system, allows users to create a computerized database, sort and retrieve data, create forms and reports from the data, as well as to add, modify, and delete data.
Valuable information normally would have numerous characteristics, such as the accuracy, verifiable, timely, accessibility, the cost-effectiveness, and many more.
The Hierarchy of Data
A character is one byte. For example, numbers, letter, space, punctuation marks, and other symbols.
A field is a combination of one or more related characters. Such as the field name, field size, and data type.
A record is a group of related fields. Normally, A primary key uniquely identifies each record. A data file is a collection of related records.
Maintaining Data
File maintenance refers to the procedures that keep data current. These procedures may refer to adding records, modifying records, or even deleting records.
Validation compares data with a set of rules or values to find out if the data is correct. Rules as such may include alphabetic or numeric check, range check, consistency check, completeness check, check gift, and other checks.
Database Management Systems
A data dictionary contains data about each file in the database and each field in those files. A DBMS provides several tools that allow users and programs to retrieve and maintain data in the database.
A query language consists of simple, English-like statements that allow users to specify the data to display, print, or store. Query by example (QBE) provides a GUI to assist user with retrieving data.
A form is a window on the screen that provides area for entering or modifying data in database. A report generator however allows users to design a report on the screen, retrieve data into the report design, and then display or print the report.
A DBMS provides means to ensure that only authorized users access data at permitted times.
Relational, Object-Oriented, and Multidimensional Databases
A data model consists of rules and standards that define how the database organizes data. A relational database on the other hard stores data in tables that consists of rows and columns. Each row normally would have a primary key whereas each column has a unique name instead. A relationship is a link within the data.
Structured Query Language is a type of query language that allows users to manage, update, and retrieve data.
An object-oriented database stores data in objects. Examples of applications appropriate for an object-oriented database include multimedia database, groupware database, computer-aided design database, and hypertext database.
A multidimensional database can store data in more than two dimensions of data. Sometimes these are also known as a hyper-cube that can consolidate data much faster than a relational database.
A data warehouse is a huge database that stores and manages the data required to analyze historical and current transactions.
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