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Unit II: Database Query using SQL


                     4                        DATABASE QUERY USING SQL














          Chapter Outline


          4.1 Database Management System (DBMS)              4.2 Relational Data Model
          4.3 Structured Query Language (SQL)                4.4 SQL Statements and Functions






        Introduction

        In Class XI, we learned the basics of database management systems and the use of structured query language for
        interacting  with  databases.  This  chapter  will  review  the  basic  terminologies  of  Database  Management  Systems
        (domain, tuple, relation, candidate key, primary key, and alternate key). We will also review the components of SQL:
        Data Definition Language (DDL) and Data Manipulation Language (DML).
        Furthermore, this chapter will explore various mathematical, text, date, and aggregate functions, equipping us with
        powerful techniques for querying and manipulating data.

        4.1 Database Management System (DBMS)

        To retrieve valuable information from data, we need to organise the data in a form that makes it easy to retrieve and
        process. Often, it is convenient to manage the data in a tabular format. Table 4.1 shows sample data about individual
        student preferences of the games they want to play.

                                   RollNo             Name                  Game
                                      1             Pushkar               Cricket

                                      2             Aadhira              Badminton
                                      3          Jayaprakash              Cricket
                                      4           Priyabrata           Table-tennis

                                      5             Farook                Cricket
                                      6             Amisha                Cricket

                                      7              Aayam              basketball
                                                         Table 4.1




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