Oracle Tutorial

 
 
 

Basic Oracle Tutorial

 
 

Before learning any DBMS it is important to be aware of few key terms which will help you in understanding things.

What is RDBMS?

RDBMS aka RELATIONAL DATABASE MANAGEMENT SYSTEM, is the software used for the management, maintenance and retrieval of the data stored in a database. RDBMS frees the programmer from the need to worry about the organization and location of data. The primary goal of a DBMS is to provide an environment which is both convenient and efficient to use in retrieving and storing information.

Example: Oracle, Microsoft SQL Server, My SQL, etc

What is DATABASE?

A database is a collection of tables that is organized so that its contents can easily be accessed, managed, and updated.

Example: School Database, which can have store information realated students, courses, student-grades, etc

School Database

What is Table?

Table is a collection of rows and columns. One table has many records.

Example: Students Table consists of all information related to students.

Table

What is Record or Row?

Single horizontal row in table is called Record or Row. One record has many columns.

Example: Single Student Information stored in table is called record. In above diagram record is highlighted in blue color.

What is Column or Field?

Single vertical row in table is called Column or Field. Column tells you about specific information.

Example: In above diagram column is highlighted in red color. Column describes specific information of any student, i.e. In above figure we can find student\'s first name based on its studentid. (StudentId - 201, FirstName is Michael)

What is Relationship?

The way in which two or more tables are connected is called relationship. There are many types of relationship with each of them have their unique purpose, we will be going to study them in depth with examples later. For now you can remember connecting two or more tables is called establishing relationship between tables.

What is Keys?

A Key is a single attribute or combination of two or more attributes of an entity set that is used to identify one or more instances of the set.

PRIMARY KEY:- A primary key is a field that uniquely identifies each record in a table. As it uniquely identify each entity, it cannot contain null value and duplicate value. Example: Student_Id in student table.

FOREIGN KEY:- A primary key referenced in another table is called Foreign key. Example: StudentId referenced in StudentsGrade table.

I believe I have explained a very basic terms in Lehman\'s language to get you started for learning any RDBMS of your choice. I will be explaining terms and concepts in more depth with practical examples.

Disclaimers: Purpose of this article was to get you familiar with some of very common RDBMS terms which we are going to use frequently while learning either Oracle, SQL Server, My SQL or any other popular RDBMS.


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