Overview of Database Management Systems
The study of earth systems and various disciplines of earth sciences increasingly rely on digital spatial data acquired from remotely sensed images analysed by geographical information systems (GIS) and visualized on paper maps or the computer screen. Geoinformatics is the science and technology which uses geographically referenced data to address such needs and problems. It utilizes technologies which deal with the structure and character of spatial information, its capture, classification, qualification, storage, processing, portrayal and dissemination. It relies on an infrastructure that is capable of addressing problems of geography, cartography, geodesy, positioning and navigation, remote sensing, spatial analysis and web mapping. It uses geographically referenced data for better understanding and interpretation of human interaction with the earth’s surface.
The science of geoinformatics uses different technologies, approaches, processes, and methods to interpret issue relating to the earth’s surface for collaborative decision making. It can combine different types of dataset – from GIS, remote sensing and non-remote sensing, and socio-economic. Results can be generated in the form of maps, charts, graphs, reports, etc. to allow better interpretation, management and decision making.
Geoinformatics has at its core the technologies supporting the processes of acquiring, analysing and visualizing spatial data. In other words, the hub of geoinformatics is a database and its management system.
DATA AND INFORMATION:
Data can be defined as a representation of facts, statistics, concepts or instructions in a formal manner which is suitable for communication, interpretation, or processing by human beings or electronic machines. Data is represented by quantities (0-9), characters (A-z, a-z), or symbols (+,-,/,*,<,>,= etc.) which form the basis of reasoning or calculation. Data can exist in a variety of forms – as numbers or text on pieces of paper, as bits and bytes stored in electronic memory, or as facts stored in a person's mind. Strictly speaking, data is the plural of datum, a single piece of information. In practice, however, people use data as both the singular and plural form of the word, and as a mass noun (like “sand”).
Data are the most important part of an organization’s information system. A company needs to save information about employees, departments, and salaries. These pieces of information are called data. Permanent storage of data are referred to as persistent data. Generally, we perform operations on data or data items to provide different kinds of information about an entity. Good, timely, relevant information is the key to decision making, and good decision making is the key to organizational survival. It must be noted that all the data will not convey useful information. Data are raw facts that constitute the building blocks of information. Useful information is obtained after processing data. In other words, data has to be interpreted in order to obtain information.
The term data is often used to distinguish binary machine-readable information from textual human-readable information. Since the mid-1900s, people have used the word data to mean computer information that is transmitted or stored. The data may be stored and transmitted in the form of electrical signals and recorded on magnetic, optical, or mechanical recording media. For example, consider the names, telephone numbers, and addresses of the people you know. Some applications make a distinction between data files (files that contain binary data) and text files (files that contain ASCII data).
With the progress of technology, an increasingly large amount of data is becoming available for storage, transmission, processing and interpretation. Over the years, numerous phrases have been used to describe data and how we use and analyse it. Massive volumes of data that is so large that it is difficult to process using traditional database and software techniques is now called Big Data. Becoming familiar with new terminology will help you to better understand the data and its role in information technology.
It is also important to know is that in database management systems (DBMS), data files are the files that store the database information, whereas other files, such as index files and data dictionaries, store administrative information, known as metadata.
WHAT IS A DATABASE:
A database is a collection of data that is well organized so that it can be easily accessed, managed and updated. In a database, data is organized into rows and columns – similar to a table. It is indexed to make it easier to find relevant information. In a database, data gets updated, expanded and deleted as new information is added. Databases process workloads to create and update themselves. They also query the data they contain and run applications in response to answers. Computer databases typically contain aggregations of data records or files. The database of a business organization may include sales transactions, product catalogs, store inventories, sales records and customer profiles. Typically, the management system of a database provides users with the ability to:
• Control read/write capability
• Combine data from different sources
• Specify report generation, and
• Analyze usage.
Some databases offer ACID (atomicity, consistency, isolation and durability) compliance to guarantee that data is consistent and that transactions are complete. This is particularly useful when banks allow their customers to manage their own accounts, or the railways allow the passengers to book their own tickets. Databases are implemented and managed through large mainframe systems. They are also present in smaller distributed workstations and midrange systems, such as IBM's AS/400 and personal computers.
Databases have evolved since their inception in the 1960s. Beginning with hierarchical and network databases, they evolved through the 1980s to object-oriented databases. Today, we are using SQL and NoSQL databases and cloud databases. On the basis of the kind of data stored, databases can be classified according to content type:
• Full text
• Numeric, and
In computing, databases are sometimes classified according to their organizational approach. There are many different kinds of databases, ranging from the most prevalent approach – the relational database – to a distributed database, cloud database or NoSQL database.
DATABASE MANAGEMENT SYSTEMS:
A database management system (DBMS) is a computer program (or more typically, a collection of programs) designed to manage a database, and run operations on the data requested by numerous users. Typical examples of DBMS use include accounting, human resources and customer support systems. The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage large amounts of data within a single software application. The DBMS manages incoming data, organizes it, and provides ways for the data to be modified or extracted by users or other programs. A DBMS interacts with end-users, other applications, and the database itself to capture and analyze data. A database management system is important because it manages data efficiently and allows users to perform multiple tasks with ease.
Components of DBMS:
1. Software – a set of programs used to control and manage the overall database.
5. Database Access Language
6. Query Processor
7. Run Time Database Manager
8. Data Manager
General Functions of a DBMS: Organizations employ Database Management Systems to help them effectively manage their data and derive relevant information out of it. Some general functions of a DBMS are:
1. Designed to allow the definition, creation, querying, update, and administration of databases
2. Define rules to validate the data and relieve users of framing programs for data maintenance
3. Convert an existing database, or archive a large and growing one
4. Run business applications, which perform the tasks of managing business processes, interacting with end-users and other applications, to capture and analyze data
Types of Database Management Systems: There are four structural types of database management systems:
1. Hierarchical databases.
2. Network databases.
3. Relational databases.
4. Object-oriented databases.
Some important examples of DBMS include MySQL, PostgreSQL, Microsoft Access, SQL Server, FileMaker, Oracle, RDBMS, dBASE, Clipper, and FoxPro.
R. Elmasri and S.B. Navathe (2011). Fundamentals of Database Systems. Addison-Wesley, Boston. 1172p. ISBN 10: 0-136-08620-8.
S. Sumathi and S. Esakkirajan (2007). Fundamentals of Relational Database Management Systems. Springer-Verlag, Berlin. 776p. ISBN 10: 3-540-84397-7