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Monday, 25 April 2016

ICS Notes Computer Science Part 2 Chapter 1 Data Basics Short Questions

ICS Notes Computer Science Part 2 Chapter 1 Data Basics Short Questions


Q 1. What is data?
Ans. Raw facts and figures are called data. It is used to perform certain operations in an organization. It gives the status of past activities. Data may be numerical like inventory figures, test scores, etc. Data may be non numerical like your name and address.

Q 2. What is information?
Ans. Processed data is called information. It is usually output of a process and is meaningful. The grade of a student in a particular subject in a semester precisely gives the complete information of the performance of a student.

Q 3. What is the difference between data and information?
Ans. Data is raw facts whereas information is processed form of data. Data is given to the computer for input and information is received from the computer in the form of output.

Q 4. Define data processing.
Ans. Data processing is any computer process that converts data into information or knowledge. The processing is usually assumed to be automated an running on a computer. It can also be defined "The manipulation of data to achieve some required objective is called data processing.

Q 5. What is data manipulation?
Ans. Applying different operations on data is called data manipulation. This operation include classification, calculation, sorting, and summarizing.

Q 6. Define field?
Ans. Each column of a table in relational database is called a field. It represents the attributes of the entity. In table it is represented as a column header.

Q 7. Define record.
Ans. A collection of related fields treated as a single unit is called record. If we collect different attributes of a student then it will be called student record.

Q 8. Define file.
Ans. A collection of related records treated as a single unit is called a file. If we collect the records of students then collective it will be called a student file.

Q 9. Name the file types from usage point of view.
Ans. Types of files from usage point of view
  • Master file
  • Transaction file
  • Back up file

Q 10. Name the file types from function point of view.
Ans.  Types of files from function point of view.
  • Program files
  • Data files

Q 11. What is program file?
Ans. A file that contains software instructions. The source files and executable files are examples of program file.

Q 12. What do you mean by file organization?
Ans. The physical arrangement of records of a file on secondary storage devices is called file organization. There are a lot of methods to store files on secondary storage. All the methods have their own advantages and disadvantages.

Q 13. Name different types of file organization?
Ans. Different types of file organization
  • Sequential files
  • Direct or random access files
  • Indexed sequential files

Q 14. What are sequential files?
Ans. In sequential files records are stored sequentially. These files store data as it arrives one after another in the sequence. These files take more time to store data. The best reason for using sequential files is there degree of portability to other program. The drawback to sequential files is that you only have sequential access to your data.

Q 15. What are direct or random access files?
Ans. In random files records are accessed directly without going through the preceding records. Record in this type of file is stored on a calculate address. In random file the data is stored exactly as it appears in memory, thus saving processing time.

Q 16. What are indexed sequential files?
Ans. The data in this type of file can be accessed sequentially as well as randomly based on a key value. As records are stored in the form of key-pointer pair in the indexed file, therefore, it requires more space on the disk as compared to random files. It's processing is as fast as random files.

Q 17. What is an index?
Ans. A database index is a data structure that improves the speed of operations on a database table. It is a table created by system developers or DBA containing the key attributes of the table for which the index is created. Indexes can be created using one or more columns of a database table, providing the bases for both rapid random lookups and efficient access of ordered records.

Q 18. Define database?
Ans. A database is a structured collection of records or data that is stored in a computer so that a program can consult it to answer queries. The records retrieved in answer to queries become information that can be used to make decisions. The term database refers to the collection of related records or related data sets or files, and the software  which is used to manipulate the database is database management system or DBMS.

Q 19.What is database management system?
Ans. A collection of programs that enables you to store, modify and extract information from a database. There are many different types of DBMS, ranging from small systems that run on personal computers to huge systems that run on mainframes. The DBMS is used for large and medium sized organizations having different types of files for different purposes.

Q 20. What is data dictionary?
Ans. DBMS uses a file to store the data definition or description of the structure of database is called data dictionary i.e. data about database. It holds the name, type, range of values, source, and authorization for access for each data elements in the organization's files and databases.

Q 21. What do you mean by consistency constraint?
Ans. These are the rules that must be followed to enter data in the database e.g. in name field there must not be a numerical value, in date of birth field there must be a date.

Q 22. What is meant by data independence?
Ans. Data independence means that data and application programs are separate from each other. Physical implementation of data is hidden from application program. DBMS lies between the application program and database.

Q 23. Name some large databases developed.
Ans. NADRA, Google, VISA and Amazon books database are a few commonly known large databases around the world.

Q 24. Write down any two disadvantages of database system.
Ans.   Disadvantages of database system
  • Additional training is required.
  • Additional hardware cost.
  • Additional software cost.

Q 25. What are the activities performed on data?
Ans. The user of database normally has the following facilities.
  • Adding new files to the database.
  • Removing existing files from the database.
  • Inserting new data into the existing files.
  • Retrieving data from existing files.
  • Updating data in existing files.
  • Deleting data from existing files.

Q 26. Name the four major components of database system.
Ans.  Four major components of database system
Data:
  • Raw facts that become information after processing.
Hardware:
The physical components of a system it includes:
  • Input / Output (I/O) Devices.
  • Primary storage
  • Secondary storage devices
  • I/O channels
  • Processor.
Software:
All kinds of programs which includes:
  • User / System software
  • Utilities
Personnel:
People who involve with the system:
  • Programmer / Analyst
  • End Users
  • Database Administrator.

Written by: Asad Hussain & Sana Hussain

1 comment:

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