Class 12 Computer Science Chapter 2 Notes

• Important chapter 2 computer class 12 for Intermediate part-II students.
• Define Field, Record and File: Field : A field is a unit of data consisting of one or more characters i.e., Roll Number, Student Name, Grade etc. Record : A collection of related data items treated as a single unit is called a record. File : A collection of related records treated as a single unit is called a file or a data set. 
• Define Data Elements, Records, Files or Datasets and Databases.
• Define Relation or Table and describe Entity.
• Important computer science class 12 chapter 2 pdf for Intermediate part-II students.
• Describe Properties of Relation: A Relation or a Table which is the basis of a Relational DBMS, by definition must have certain inherent characteristics that form the basic for its underlying strength and flexibility. Because of these features, an application implemented by using such a system is much more flexible and can be easily modified when alterations or enhancements to the underlying data base take place. These characteristics are:
• Important computer class 12 chapter 2 for Intermediate part-II students.
• Describe Views: Views are created by using SQL, which is a powerful database language, used for data definition and data manipulation purposes. The purpose of using views is purely to keep the data safe and secure from un-authorized and illegal users. The views provide the descriptions of relations that are not stored, but constructed as needed from stored relations.
• Describe Indexes: It is another table created by the system developer / DBA containing the key attributes of the table for which the Index is created. It has a very vital role in the database management systems, especially in RDBMS. The important associations defined in the system make use of this. It helps the system run smooth and fast. 
• Define Key? Describe Types of Keys.
• Important computer science chapter 2 class 12 for Intermediate part-II students.
• Define User: The user or end-user is simply a person who uses the computers for his specific need. He might have a moderate knowledge of computers, computer science and information technology, and his need to use the computers may be entertainment, education, or professional tasks. He does not need to know the in-depth knowledge of 10 the computer systems, but instead, he should be aware of the installed software he intends to use. 
• Define The Data Administrator: A data administrator (DA) is responsible for the entire data of an organization. He normally develops the overall functional requirements for the databases being used m the office. He shares in developing the logical design for each database. He should control and manage the databases, establish the data standards, supervise the data distribution within the organization and communicate with the users when necessary. He should also participate in developing the data dictionary, prepare documentation and conduct user training where needed. Normally, the Data Administrator serves as a bridge between users and data processing staff.
• Important computer science class 12 chapter 2 for Intermediate part-II students.
• Define The Database Administrator: A database administrator (DBA) is responsible for the design, implementation, operation, management and maintenance of the database. He / She must be technically expert on the overall intricacies of the database and DBMS. He is supposed to plan, coordinate and carry out a variety of jobs during all phases of the database projects. He must possess the technical skills because he has to work on the complex software and hardware issues involved and to solve the problems of the system and application experts in the organization. He is also responsible to make sure the database access rights, to safeguard its security and to maintain and fine-tune the database functionality.