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i +  TYPES OF DATABASES

                  There are mainly two types of databases:
                  •  Flat File Database: It is a type of database that contains records having a less
                     number of fields without any structured relationship between them. The most
                     popular example of a flat file database is Excel 2016.                                  Excel 2016
                  •  Relational Database: It is a type of database that stores
                     data in multiple tables and links those tables together
                     to retrieve the information.  Commonly used relational
                     database systems are Microsoft Access, Microsoft SQL Server, ORACLE, etc.
                     Info Byte

                      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 (RDBMS).



                   i +  TERMS RELATED TO A DATABASE

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

                                                                   FIELDS
                      Primary
                        key
                                  Reg No. Name                   Father’s Name       Date of Birth       Class
                                  187/11     Krishna Kant        Mr. K.S. Kant       15/08/2007             VIII
                             RECORDS  156/12  Rishi Sharma       Mr. N.K. Sharma     22/10/2008              IX

                                  194/11
                                                                                     16/04/2008
                                                                                                             IX
                                             Suraj Patel
                                                                 Mr. G.S. Patel
                                  123/12     Priyansh Sagar      Mr. P.K. Sagar      18/06/2007             VIII
                                                        Table: Student's detail
                  The commonly used terms in a relational database are:
                  •  Table: Table is also knowns as Relation. 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 columns are also known as a Fields. A set of
                     values for the fields is called a Record. A 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 the above table, 'Student's detail' the
                     'Reg No.' can be referred to as a primary key as it is always unique and never null.
                  •  Query: A query is the most powerful object in a database. It helps you retrieve information
                     from a table based on some criteria or conditions. You can find and retrieve data from the
                     database by creating and running a query.
                  •  Report: A report is a database object that is specially designed to display or print the data
                     in a formatted way. It is the final result of the manipulated data that comes from tables or
                     queries in a DBMS is known as a report.







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