In the language of computers, we define data as the collection of information. The facts that can be recorded and which have implicit meaning known as ‘data’. On the other hand, Database is a collection of interrelated data. DBMS or the database management systems are a study of such topics. In the following section, we will introduce the Function of DBMS and purpose of having a database management system. Let us start.
DBMS – Purpose
It is a collection of programs that enables the user to create and maintain a database. In other words, it is general-purpose software that provides the users with the processes of defining, constructing and manipulating the database for various applications.
Database systems are designed to manage large bodies of information. Management of data involves both defining structures for storage of information and providing mechanisms for the manipulation of information. In addition, the database system must ensure the safety of the information stored, despite system crashes or attempts at unauthorized access. If data are to be shared among several users, the system must avoid possible anomalous results.
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Disadvantages in File Processing
A database management system (DBMS) is a collection of interrelated data and a set of programs to access those data. This is a collection of related data with an implicit meaning and hence is a database. The collection of data, usually referred to as the database, contains information relevant to an enterprise. The primary goal of a DBMS is
to provide a way to store and retrieve database information that is both convenient and efficient. By data, we mean known facts that can be recorded and that have implicit meaning.
For example, consider the names, telephone numbers, and addresses of the people you know. You may have recorded this data in an indexed address book, or you may have stored it on a diskette, using a personal computer and software such as DBASE IV or V, Microsoft ACCESS, or EXCEL.
The following are the main disadvantages of DBMS in File Processing:
- Data redundancy and inconsistency.
- Difficult in accessing data.
- Data isolation.
- Data integrity.
- Concurrent access is not possible.
- Security Problems.
Advantages of DBMS
Because information is so important in most organizations, computer scientists have developed a large body of concepts and techniques for managing data. These concepts and technique form the focus of this book.
- Data Independence.
- Efficient Data Access.
- Data Integrity and security.
- Data administration.
- Concurrent access and Crash recovery.
- Reduced Application Development Time.
Application or Function of DBMS
Following fields are where the main Database Applications lie:
- Banking: all transactions
- Airlines: reservations, schedules
- Universities: registration, grades
- Sales: customers, products, purchases
- Online retailers: order tracking, customized recommendations
- Manufacturing: production, inventory, orders, supply chain
- Human resources: employee records, salaries, tax deductions
Data Processing Vs. Data Management Systems
Although Data Processing and Data Management Systems both refer to functions that take raw data and transform it into usable information, the usage of the terms is very different. Data Processing is the term generally used to describe what was done by large mainframe computers from the late 1940’s until the early 1980’s (and which continues to be done in most large organizations to a greater or lesser extent even today): large volumes of raw transaction data fed into programs that update a master file, with fixed format reports written to paper.
The term Data Management Systems refers to an expansion of this concept, where the raw data, previously copied manually from paper to punched cards, and later into data entry terminals, is now fed into the system from a variety of sources, including ATMs, EFT, and direct customer entry through the Internet.
The master file concept has been largely displaced by database management systems, and static reporting replaced or augmented by ad-hoc reporting and direct inquiry, including downloading of data by customers. The ubiquity of the Internet and the Personal Computer have been the driving force in the transformation of Data Processing to the more global concept of Data Management Systems.
Some Important Concepts Of DBMS
A database management system (DBMS) is a collection of interrelated data and a set of programs to access those data. This is a collection of related data with an implicit meaning and hence is a database.
A datum – a unit of data – is a symbol or a set of symbols which is used to represent something. This relationship between symbols and what they represent is the essence of what we mean by information.
Knowledge refers to the practical use of information. The collection of information stored in the database at a particular moment is called an instance of the database.
The overall design of the database is called the database schema. The physical schema describes the database design at the physical level, while the logical schema describes the database design at the logical level.
A database may also have several schemas at the view level, sometimes called subschemas, that describe different views of the database.
Application programs are said to exhibit physical data independence if they do not depend on the physical schema, and thus need not be rewritten if the physical schema changes.
Underlying the structure of a database is the data model: a collection of conceptual tools for describing data, data relationships, data semantics, and consistency constraints.
A database system provides a data definition language to specify the database schema and a data manipulation language to express database queries and updates.
One of the main reasons for using DBMSs is to have central control of both the data and the programs that access those data. A person who has such central control over the system is called a database administrator (DBA).
Q 1: Which of the following statements are not correct?
A) The data is the collection of information.
B) Data isolation is one of the main advantages of DBMS
C) Concurrent access and Crash recovery are one of the advantages of DBMS.
D) Both B) and C).
Ans: B) Data isolation is one of the main advantages of DBMS.