Introduction to Database - Learn Data Science

Table of Contents

Data

Data are raw fact that have no specific meaning.

Information

Information is processed data that has purpose and meaning.

Difference Between Data and Information

Data Processing

Data is a collection of facts & figures, such as values or measurements. The data is the raw material to be processed by a computer.

Data are manipulated to produce output. when this output can be used to help people make decisions, it is called information.

Data processing is defined as series of actions or operations that convert data into useful information.

Data processing also refers to the complete check of the data validity , accuracy, consistence, integrity and its relevance to the client’s requirements.

Input

Input is the task where verified data is coded or converted into machine readable form so that it can be processed through a computer.

Processing

Processing is when the data is subjected to various means and

methods of manipulation, the point where a computer program is being executed, and it contains the program code and its current activity.

classifying,
sorting,
calculating,
summarizing,
comparing

Output

Output is presented to users in various report formats like printed report, audio, video, or on monitor.

Storage

Storage is used to store information for future use and reporting

Database Terminology

Column or Field

A single attribute or piece of data in a table. Each column typically has a name and a data type.

Row or Record –

A single set of fields in a table, representing a single entity (such as a person, product, or transaction).

Table

A structured set of data elements (fields) using a fixed number of columns and rows. In relational databases, tables are used to store data.

Primary Key

Unique and mandatory. It ensures that each row can be uniquely identified and accessed.

Foreign Key

A field in one table that refers to the primary key in another table. It establishes a relationship between the two tables

Relationship

A relationship refers to the association between tables. Relationships are established to connect data in one table to data in another table. The relationship can be:

One to one (1-1)
One to many (1-M)
Many to One (M-1)
Many to Many (M-M)

Field, Record and Table

Table

A set of data arranged in a columns and rows. The column represent characteristics/properties of stored data and the row represent the actual data entries.

E_ID	E_NAME	E_SALARY
1	RAM	60000
2	SHYAM	45000
3	SITA	56000
4	GITA	70000
5	HARI	80000

Field

Fields are columns in a table with specific information about the data.

In above table e_id, e_name and and e_salary are fields that provides the information about id , name and salary of different employees.

Record

Record is a individual entry that exists in a table. It is also known as row.

Records give the complete information of a single entry or entity.

E_ID	E_NAME	E_SALARY
1	RAM	60000
2	SHYAM	45000
3	SITA	56000
4	GITA	70000
5	HARI	80000

In above table selected row gives the complete information of about the particular employee sita.

Collections of records and fields makes a table and a collection of tables makes a database.

Database

Database is an organized collection of structure data or information that is stored in such a way that it can be easily accessed , create, update, delete and managed.

A database is usually controlled by a database Management System (DBMS)

In Database, data are organized in row and columns in the form of table.

Most database use structure query language (SQL) for writing and querying data.

SQL , MYSQL, Oracle, PostgreSQL are the example of database.