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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. Indeed, data has been stored in manual registers
in the form of tables since time immemorial. Table 9.1 shows sample data about individual students preferences for
the games they want to play.
+---------+-------------+--------------+
| Roll_No | 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 9.1: Game preferences
Each row in Table 9.1 has data about one student's preference for a game. Column headings describe the information
stored in the columns. Thus, for each student, RollNo, Name, and Game are stored in the first, second, and third
columns respectively. In addition to the user data, DBMS also keeps a description of the stored data, called metadata
(also called data about data). For example, in the above example, DBMS may store the table's name, names of columns,
and the type of data that columns contain.
Metadata: Description of data like names of tables, names and types of attribute.
9.1.1 DBMS Users
For creating and managing databases, several application programs are required. Database Management System
(DBMS) is a collection of programs that help define, construct, and manipulate the database. Database definition
includes specifying the structure of the database, the type of data, and the restrictions imposed on the data.
Database construction deals with storing the actual data in the database. Finally, database manipulation deals with
the modification or retrieval of data. Fig 9.2 represents a database system that comprises DBMS software and the
database. Note that the DBMS acts as an interface between end-users and the database. As every access to data in a
DBMS must go through a DBMS, it can control access to data by checking against unauthorised access to data. Since
several end-users may access the same database, DBMS facilitates sharing of data. Users of DBMS may belong to any
of the five types:
1. End Users: Users who use the DBMS for retrieving or modifying the data.
2. Database Administrator (DBA): A Person who manages the entire database by controlling access and acquiring
resources (both hardware and software).
DBA: Responsible for defining data to be stored and access rights of various types of users.
3. Database Designers: People who analyse the requirements of the end-users and design the structure of the database.
4. Systems Analysts: People who analyse the data requirements of the end-users and arrive at the objectives and
descriptions of the database.
5. Application Programmers: People who develop programs to meet the objectives identified by the systems analysts.
232 Touchpad Informatics Practices-XI

