Page 23 - TechPluse_C8_Flipbook
P. 23

Relational Databases
                 Clickipedia



                   The  relational  database  was  proposed  by  Edgar F.  Codd.  He  gave  a  set  of  thirteen rules
                   (Codd’s rules) to define a Relational Database Management System.

                     ADVANTAGES OF A DATABASE SYSTEM

                 A database system has many advantages. Some of the important advantages are:

                    It minimizes the redundancy of data by integrating and sharing the data files.
                    It saves the storage space.

                    All the users are provided with some access rights or privileges and permissions.
                    The files can be easily updated whenever changes are being made.

                     TERMS RELATED TO A DATABASE

                 Data is stored in the table of a database, as shown in below diagram.

                                                               FIELDS


                                                               Father’s Name
                                                                                   Date of Birth
                                               Name
                              Reg No.    Aashi Kant          Mr. P.S. Kant        15/08/2007           Class
                                                                                                        VIII
                              187/11
                         RECORDS  156/12  Nazia Sharma       Mr. R.K. Sharma      22/10/2008             IX
                                         Rajesh Patel
                              194/11
                                                                                  16/04/2008
                                                                                                         IX
                                                             Mr. V.S. Patel
                              123/12     Niraj Sagar         Mr. A.K. Sagar       18/06/2007            VIII
                 The commonly used terms of the relational database are:
                     Table: It is a group of related data organised in columns and rows in a database. The columns
                     contain a number of headings such as Reg No., Name, Father's Name, Date of Birth, Class,
                     etc. These are known as Fields. A set of values for the fields is called a Record. Record is one
                     row of the table.
                     Primary Key: It is a unique field by which the records are uniquely identified in a table. A
                     table can have only one primary key. For example, in a student’s record the ‘Reg No.’ can be
                     called a primary key.

                     Query: A query is the most powerful feature of database. It helps you to retrieve information
                     from a table based on some criteria or condition. You can ask, find and retrieve data from
                     the database just by creating and running the query.


                                                                               Introduction to LibreOffice Base       21
   18   19   20   21   22   23   24   25   26   27   28