Class 12 Computer Science Notes
Chapter No 1
Data Basics
Answer the following question.
Differentiate between data and information. What activities are involved in data processing. Discuss in detail based on data basics?
Answer.
Difference between data and information
The difference between data and information is as follows:
| Data
| Information
|
| Data may be a assortment of RAW facts and figures. | Information is processed form of data. |
| It is used as input in the computer. | It is the output of the computer. |
| It is normally used in its volume. | It is normally short in its volume. |
| It is difficult or even impossible to reproduce. For example, it is hard to reproduce census data if it is lost | It is easier to reproduce. For example, literacy rate can be we calculated from the stored data. |
| It is used rarely. | It is used frequently. |
Data basic processing activities
Data processing is any computer process that converts data into information on knowledge. The processing is usually as you want to be automated and running on a computer. It can also be defined the manipulation of that are to achieve some required objective is called data processing.
- Define file, record and field in details?
Ans. Define file
A collection of connected records treated as one unit is named a file. If we have a tendency to collect the records of students then collective it’ll be known as a student file.
Define record
A collection of connected fields treated as one unit is named record. If we collect totally different attributes of a student then it’ll be known as student record.
Define field
Each column of a table in on-line database is named a field. It represents the attributes of the entity. In table it’s depicted as a column header.
- Describe the file types from uses point of view and functional point of view?
Ans. Types of files from usage point of view
- Master file
- Transaction file
- Back up file
Types of files from function point of view.
- Program files
- Data files
- How do we organize the file on storage media?
Ans. The physical arrangement of records of a file on secondary storage devices is called file organization. There are a great deal of ways to store files on external storage. All the methods have their own advantages and disadvantages
Different types of file organization of files in storage media.
- Sequential files
- Direct or random access files
- Indexed sequential files.
- In general, what activities are to be performed on the databases? Discuss in details.
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.
- What are the four major components of the database system? Write in details.
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.
- Discuss the objectives of the databases in your own words.
Ans. A group of programs that allows you to store, modify and extract information from a database
The software is employed for big and medium sized organizations having differing kinds of files for various functions.
- Describe the different database model?
Ans. Database Model
A information model is that the logical structure of a information. It reminds how data is stored, organised and manipulated.
Types of Database Models
- Hierarchical database model
The hierarchical database model a logical structure that organize data in tree like form. It represents data elements with owner and subordinate relationship. The data elements in a subordinate relationship are called members. The data elements that have subordinate are called owners. A subordinate can have only a single owner. The data element of the top-most level has no owner. The hierarchical model is suitable to desire describe many relationships in real world like table of contents and department of a university etc.
- Network database model
The network model is a logical structure in which some data elements can have more than one owner. It is more complex than hierarchical model. It also provides more flexibility.
- Relational database model
The relational model is a logical structure that stores data in relation. A relation is a term used for table. A table consist of rows and columns. One row of a table represents one record. Each column of a table represent a field of attribute. The tables are linked with each other by common fields. The relation model provides more data independence. It is more flexible then hierarchical and network database models. It is most commonly used database model.
- Object oriented database model
The object oriented model is a logical structure that stores objects instead of data like integers, real numbers or strings. An object in the real world has two characteristic of state and behaviour. The state is represented by the data. The behaviours is represented by the functions in programming language. Objects are used in object oriented programming languages such as Java and C++. The object oriented database are also called object database management system.
- Object relational database model
The object relational model is a database management system that is very similar to relational database. However, it uses object oriented approach. The data is stored in the database as object the data can be manipulated using a query language. Oracle is the leading object relation relational data base management storage.
- What are the advantage and disadvantage of the the database management system.
Ans.
| Advantages of database system
| Disadvantages of database system
|
| Reduce Data Redundancy
| Extra training is required.
|
| Data Consistency
| Extra hardware cost.
|
| Data Integrity
| Extra software cost. |
Data basics MCQs
Fill in the blanks.
>> DBMS stands for database management system.
>> A record is a collection of related fields.
>> A file is a collection of records.
>> Before processing the data is recorded in transaction files.
>> A databaseis a collection of logically related data.
>> The definitions is stored in data dictionary.
>> SQL stands for structured query language.
>> Hierarchical data model has the general shape of a (n) organization chart.
>> Data is a collection of facts, figures and statics.
>> Process data is called information.
Choose the correct option.
Which of the following represents a collection of concept that are used to describe the structure of a database?
Data warehouse
Data model
Data Structure
Data type
Which of the following data model is more flexible?
Network data model
Hierarchical data model
Relational data model
Object data model
Which of the following type of file required largest processing time?
Sequential file
Random file
Indexed sequential file
Direct Access file
Which of the following may be a temporary file?
Master file
Transaction file
Backup file
None of these
SQL is a (n):
Unstructured language
Structured language
Object oriented language
Software