Data is a collection of facts – unorganized, but able to be organized into useful information. A collection of sales orders, employee time sheets, and class attendance cards are a few examples. Data can be manipulated to produce output, such as bills, employee salary slips, and student attendance reports. This output, called information, is organized facts that helps people to make decisions. Hence, information is data arranged in an order and form that is useful to people who receive it.
Processing, in general terms, is a series of actions or operations that converts some input into useful output. In data processing, input is data, and useful output is information. Hence, data processing is a series of actions or operations that converts data into information. It consists of three sub-activities – capturing input data, manipulating it, and producing output information.
A data processing system includes resources such as people, procedures and devices used to process input data for producing desirable output.
Hence, data is raw material of information, and just as a manufacturing process transforms raw materials into finished products, data processing transforms raw data into information.
- [#1] – Introduction to Computer Fundamentals
- [#2] – Basic computer organization
- [#3] – Number systems
- [#4] – Computer Codes
- [#5] – Computer Arithmetic
- [#6] – Processor and Memory
- [#7] – Secondary Storage Devices
- [#8] – Input-Output Devices
- [#9] – Computer software
- [#10] – Planning the Computer Program
- [#11] – Computer Languages
- [#12] – System Implementation and Operation
- [#13] – Operating Systems
- [#14] – Application Software packages
- [#15] – Business Data Processing
- [#16] – Data Communications and Computer Networks
- [#17] – The Internet
- [#18] – Multimedia
- [#19] – Classification of Computers
- [#20] – Introduction to C Programming Language
Points To Remember:
- Data processing is a series of actions or operations that converts data into information. Hence, data is raw material of information, and just as a manufacturing process transforms raw materials into finished products, data processing transforms raw data into information.
- A data processing system includes resources such as people, procedures, and devices used to process input data for producing desirable output.
- The six levels of data aggregation used in data storage hierarchy of data processing consist of bit, character, field, record, file, and database.
- Multiple related bits are combined to form a character, multiple related characters are combined to form a field, multiple related fields are combined to form a record, multiple related records are combined to form a file, and multiple related files are intergrated to form a database.
- Two standard methods used in data processing for organizing data are file-oriented approach and database-oriented approach.
- In file-oriented approach of organizing data, an application’s data is organized into one or more files and the application program(s) processes the data stored in these files to generate desired output. A set of programs is provided to facilitate users to organize, create, delete, update, and manipulate their files. All these programs together form a File Management System (FMS).
- In database-oriented approach of organizing data, data from multiple related files are intergrated together in the form of a database having following properties:
It provides greater query flexibility.
It reduces data redundancy.
It solves data integrity (inconsistency) problem.
It makes data independent of application programs. That is, fields can be added, changed, and deleted from database without affecting existing programs.
It also includes data security features at database level, record level, and even at field level to provide greater flexibility of restricted data access.
- A set of programs is provided to facilitate users to organize, create, delete, update, and manipulate their data in a database. All these programs together form a Database Management System (DBMS).
- File organization deals with physical organization of records of a file for convenience of their storage and retrieval. Three file organizations used commonly in business data processing applications are sequential, direct/random, and indexed sequential.
- File utilities are routines to perform generalized operations on data files. Operations performed by some commonly used file utilities are sorting, searching, merging, copying, printing, and maintenance.
- A database model defines the manner in which various files of a database are linked together. Four commonly used database models are hierarchical, network, relational, and object-oriented.
- Four major components of a database management system (DBMS) are data definition language (DDL), data manipulation language (DML), query language, and report generator.
- Data definition language (DDL) is used to define the structure of a databse. Database structure definition is known as database schema.
- Data manipulation language (DML) includes commands to enable users to enter and manipulate data.
- Query language enables users to define their requirements as queries for extracting desired information from a database.
- Report generation enables users of a database to design the layout of a report in desired format.
List of Questions:
- What is the difference between data and information?
- What is data processing?
- What is a data processing system?
- Describe the various levels of data aggregation used in data storage hierarchy of data processing.
- Write an example to illustrate the relationship among a character, a field, a record, and a file.
- What is a database? How it is different from file?
- What are the two standard methods used in data processing systems for organizing data? Explain their relative advantages and disadvantages.
- Describe three drawbacks of traditional information processing systems that use separate, unrelated files.
- What is the difference between a master file and a transaction file?
- What is key field? How it is useful?
- What is data redundancy? Explain with an example. Now explain how database-oriented approach of data organization helps in reducing data redundancy as compared to file-oriented approach.
- What is data integrity problem? Explain how database-oriented approach of data organization helps in solving this problem.
- What is a file management system?
- Describe various types of files commonly supported in a typical file management system.
- What is the difference between an output file and a report file?
- What is a backup file? Why is regular creation of backup files important?
- What is file organization? What are three commonly used file organizations in business data processing? How do we decide to use a particular file organization for an application?
- What is a sequential file? What storage medium is used normally for storing sequential files? Write examples of few applications that can benefit from use of sequential files.
- What is activity ratio in file processing? What type of file organization is suitable for (a) an application that has high activity ratio, (b) an application that has low activity ratio? Write an example of each type of application.
- How a sequential file is organized? How records in a sequential file are accessed? How these records are processed?
- What is a direct file? What storage medium is used normally for storing direct files? Write examples of few applications that can benefit from use of direct files.
- How a record is stored in a direct file? How its is retrieved and processed?
- Explain how records in a direct file are physically organized so that it becomes possible to access a particular record directly, given its key field value.
- What is hashing? How it is useful in direct file organization? What is a collision? How it is handled?
- If activity ratio is high, use of direct files proves to be very inefficient as compared to sequential files. Explain why.
- Explain the basic principle used in indexed sequential file organization. Explain roles of data file and index file in indexed sequential file organization.
- How records are stored in an indexed sequential file? How they are retrieved and processed?
- Explain how indexed-sequential files can be used quite efficiently for both sequential and direct access processing.
- Discuss advantages and limitations of sequential, direct and indexed sequential file organizations.
- What are file utilities?
- Differentiate between sorting and merging of files.
- Explain the use of following file utilities: copying, searching, printing, and maintenance.
- What is a database management system?
- What is a database model? Name four commonly used database models. Describe any two.
- Write short notes on:
Hierarchical database model
Network database model
Relational database model
Object-oriented database model
- Explain relational database model with an example. List its main advantages as compared to hierarchical and network database models.
- If new type of data is to be added to an existing relational database, it is not necessary to redesigned the database afresh. Discuss this statement. Write an example to illustrate this.
- List some key features found in object-oriented database model that are absent in conventional database models.
- Why is object-oriented database model preferred for database applications such as CAD, CAM, CAE, CASE, expert systems, and multimedia systems?
- Explain object-oriented database model with an example.
- What are four major components of a database management system (DBMS)? Describe roles of each of these components in overall design and usage of a database.
- What is a data definition language (DDL)? What is its role in overall design and/or usage of a database?
- What is a query language? What is its role in overall design and/or usage of a database?
- What is the difference between data manipulation language and query language with respect to what each enables users to do?
- What is a report generator? What is its role in overall design and/or usage of a database?
- A report generator can be instructed to perform arithmetic operations on data found in numeric fields to make a report more meaningful and useful. Discuss this statement. Write an example to illustrate this.
- What is a database schema? What does it typically include about a database?
- What are the jobs and responsibilities of a database administrator?
- What is data dictionary? How it is created and updated?
- What is SQL? How it is useful?
- List in proper sequence, three basic steps involved in creating a database. Describe these steps.
- What are forms? List a few features found in forms that facilitate easier data entry.
- What is a filter? Explain with an example.
- List three features commonly supported in modern database systems that enable searching of desired information from a database.
- Explain with an example the use of “Find” command in making a database query. What are the limitations of “Find” command?
- Explain with an example the use of a query language in making a database query. What are the advantages of using a query language against “Find” command?
- What is query by example (QBE)? How does it make the job of querying a database simpler?
- A DBMS derives much of its power from ease with which its users can search for desired information from large volume of data stored in a database. Discuss this statement.
- What is a report? How it is created and used? Write an example of a sample report.
- Write short notes on:
Data storage hierarchy
Output versus report files
Master versus transaction files
File-oriented versus database-oriented approaches of organizing data
- Write short notes on:
Sequential file organization
Direct file organization
Indexed sequential file organization
- Write short notes on:
- Write short notes on:
Components of a DBMS
Query features in database systems