Database is a repository of collection of related data or facts.
Data in a database in most commonly viewed in one or more two-dimensional tables, each consisting of columns and rows. The entire collection or related data in one table is referred to as a File or a Table. Each row in a table represents a Record, which is a set of data for each database entry. Each table column represents a Field, which groups each piece or item of data among the records into specific categories or types of data.
Manipulation of a Database:
We may manipulate the database in one or more of the following ways:
- Performing Calculations on data
- Editing the database
- Report Generation
Searching is the process to select a desired specific data from a database. For instance, you want to select the student ranking first in a class with respect to the total marks or in individual subject or you.
Want to see the performance of a particular student. Searching is done using database commands on the relevant field.
Sorting is the process of arranging the data in a table in some order. In the above example, we may arrange the list of staff-members in an alphabetical order or according to the seniority in position or date of joining or in any other order we like.
In the case of the student database, you may sort the passed students and failed students separately or you may sort the students in the ascending or descending order of their total marks, and so on.
Merging is a process of joining data from two or more tables of the same or different databases. For examples, in a student database, you may have mark list for different classes. You want to prepare one table that shows all the first ranking students of each class. For this purpose, you can independently search in each table to select the first rank student from each class and merge all the names together in a single file/table.
Performing Calculations on data
You may do any kind of arithmetic calculations on the data stored in the database. For example, to obtain the total marks of all the subjects of a student, you may add the marks in the concerned fields of the database and store them in a separate field.
There are time when viewing the entire table in unwieldy. Using a Filter is a way laminating the information that appears on screen. Filters are a feature for displaying and browsing a selected list.
Or subset or records from a table. The visible records satisfy the condition that the user sets. Those that do not satisfy the condition are hidden.
Editing the Database
Editing is a process of performing corrections on the existing data, deleting the existing data, fields, or records, adding new data, fields, records or changing the format of the database, and so on.
You may generate any desired report, from the data of the database. For example, in the case of student database, you may generate a report of all the students who have scored marks less than the minimum marks required for a pass, and another report that gives the list of passed students, and so on.
Next: Types of Database