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CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System Complete Notes

CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System Complete Notes

CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System : The CBSE board conducts research and based on that, it evaluates its syllabus and educational pattern. CBSE provides standard education to all and also promotes a state-of-the art environment that makes students vivacious and competent in all aspects. CBSE Syllabus is well-structured as several proficient subject experts are associated with this board. The syllabus of CBSE Maths, CBSE Science along with other syllabus are amended from time to time to make students up-to-date with current information so that they can meet all educational demands confidently.

CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System Complete Notes

CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System : Download CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System  study material in PDF format. My  Team Members provides Here CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System Complete Notes and CBSE Class 12 Commerce Information Practices Sample papers. The topics are given under following  this unit :

Review of RDBMS from Class XIDatabase Fundamentals Concept of Database Transaction, Committing and revoking a Transaction using COMMIT and REVOKE,Grouping Records: GROUP BY, Group functions – MAX(), MIN(), AVG(), SUM(), COUNT();using COUNT(*), DISTINCT clause with COUNT, Group Functions and Null Values,Displaying Data From Multiple Tables: Cartesian product, Union, concept of Foreign Key, Equi-Join

Creating a Table with PRIMARY KEY and NOT NULL constraints, adding a Constraint, enabling Constraints, Viewing Constraints, Viewing the Columns Associated with Constraints;

ALTER TABLE for deleting a column, ALTER TABLE for modifying data types of a column DROP Table for deleting a table;

CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System Complete Notes

CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System :  A relational database management system (RDBMS) is a database management system (DBMS) that is based on the relational model as invented by Edgar F.Codd, of IBM’s San Jose Research Laboratory. In 2017, many of the databases in widespread use are based on the relational database model. RDBMSs have been a common choice for the storage of information in new databases used for financial records, manufacturing and logistical information, personnel data, and other applications since the 1980s. Relational databases have often replaced legacy hierarchical databases and network databases because they are easier to understand and use. However, relational databases have received unsuccessful challenge attempts by object database management systems in the 1980s and 1990s (which were introduced trying to address the so-called object-relational impedance mismatch between relational databases and object-oriented application programs) and also by XML database management systems in the 1990s. Despite such attempts, RDBMSs keep most of the market share, which has also grown over the years.

Download Here CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System Complete Notes In PDF Format

CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System Complete Notes

CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System : RDBMS stands for Relational Database Management System. RDBMS data is structured in database tables, fields and records. Each RDBMS table consists of database table rows. Each database table row consists of one or more database table fields.

RDBMS store the data into collection of tables, which might be related by common fields (database table columns). RDBMS also provide relational operators to manipulate the data stored into the database tables. Most RDBMS use SQL as database query language. Edgar Codd introduced the relational database model. Many modern DBMS do not conform to the Codd’s definition of a RDBMS, but nonetheless they are still considered to be RDBMS.

According to DB-Engines, in May 2017, the most widely used systems are Oracle, MySQL (open source), Microsoft SQL Server, PostgreSQL (open source), IBM DB2, Microsoft Access, and SQLite (open source).

According to research company Gartner, in 2011, the five leading commercial relational database vendors by revenue were Oracle (48.8%), IBM (20.2%), Microsoft (17.0%), SAP including Sybase (4.6%), and Teradata (3.7%).

According to Gartner, in 2008, the percentage of database sites using any given technology were (a given site may deploy multiple technologies):[3]

  • Oracle Database – 70%
  • Microsoft SQL Server – 68%
  • MySQL (Oracle Corporation) – 50%
  • IBM DB2 – 39%
  • IBM Informix – 18%
  • SAP Sybase Adaptive Server Enterprise – 15%
  • SAP Sybase IQ – 14%
  • Teradata – 11%

CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System Complete Notes

CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System : The term “relational database” was invented by E. F. Codd at IBM in 1970. Codd introduced the term in his seminal paper “A Relational Model of Data for Large Shared Data Banks”. In this paper and later papers, he defined what he meant by “relational”. One well-known definition of what constitutes a relational database system is composed of Codd’s 12 rules. However, many of the early implementations of the relational model did not conform to all of Codd’s rules, so the term gradually came to describe a broader class of database systems, which at a minimum:

  • Present the data to the user as relations (a presentation in tabular form, i.e. as a collection of tables with each table consisting of a set of rows and columns);
  • Provide relational operators to manipulate the data in tabular form.

The first systems that were relatively faithful implementations of the relational model were from the University of Michigan; Micro DBMS (1969), the Massachusetts Institute of Technology;[9] (1971), and from IBM UK Scientific Centre at Peterlee; IS1 (1970–72) and its followon PRTV (1973–79). The first system sold as an RDBMS was Multics Relational Data Store, first sold in 1978. Others have been Ingres and IBM BS12.

The most common definition of an RDBMS is a product that presents a view of data as a collection of rows and columns, even if it is not based strictly upon relational theory. By this definition, RDBMS products typically implement some but not all of Codd’s 12 rules.

A second school of thought argues that if a database does not implement all of Codd’s rules (or the current understanding on the relational model, as expressed by Christopher J Date, Hugh Darwen and others), it is not relational. This view, shared by many theorists and other strict adherents to Codd’s principles, would disqualify most DBMSs as not relational. For clarification, they often refer to some RDBMSs as truly-relational database management systems (TRDBMS), naming others pseudo-relational database management systems (PRDBMS).

CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System Complete Notes

CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System : A relational database management system (RDBMS) is a database engine/system based on the relational model specified by Edgar F. Codd–the father of modern relational database design–in 1970.

Most modern commercial and open-source database applications are relational in nature. The most important relational database features include an ability to use tables for data storage while maintaining and enforcing certain data relationships.

In 1970, Edgar F. Codd, a British computer scientist with IBM, published “A Relational Model of Data for Large Shared Data Banks.” At the time, the renowned paper attracted little interest, and few understood how Codd’s groundbreaking work would define the basic rules for relational data storage, which can be simplified as:

  1. Data must be stored and presented as relations, i.e., tables that have relationships with each other, e.g., primary/foreign keys.
  2. To manipulate the data stored in tables, a system should provide relational operators – code that enables the relationship to be tested between two entities. A good example is the WHERE clause of a SELECT statement, i.e., the SQL statement SELECT * FROM CUSTOMER_MASTER WHERE CUSTOMER_SURNAME = ’Smith’ will query the CUSTOMER_MASTER table and return all customers with a surname of Smith.

Codd later published another paper that outlined the 12 rules that all databases must follow to qualify as relational. Many modern database systems do not follow all 12 rules, but these systems are considered relational because they conform to at least two of the 12 rules.

Most modern commercial and open-source database systems are relational in nature and include well-known applications, e.g., Oracle DB (Oracle Corporation); SQL Server (Microsoft) and MySQL and Postgres (open source).

An object database (also object-oriented database management system, OODBMS) is a database management system in which information is represented in the form of objects as used in object-oriented programming. Object databases are different from relational databases which are table-oriented. Object-relational databases are a hybrid of both approaches.

CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System Complete Notes

CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System : CBSE Class 12 Information Practice Sample Paper-03 (2016-17) is issued by CBSE, New Delhi for March 2017 examination. Questions are Realizing the importance of the Internet, Ms. Shikha a Mathematics teacher, has decided to use Internet as a medium to teach her students Mathematics in an interesting way.

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CBSE Class 12 Commerce Information Practices Unit 3 Relational Database Management System Complete Notes

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