RDBMS Concepts

RDBMS stands for Relational Database Management System. It is a database management system (DBMS) that is called RDBMS that is supported by E. F. Codd rules. (https://en.wikipedia.org/wiki/Codd%27s_12_rules)

Examples of RDBMS are:

·        MS SQL Server

·        IBM DB2

·        Oracle

·        MySQL

·        Sybase

·        Microsoft Access and

·        Postgre SQL

Table

Table (entity) is a collection of related data entries and it consists of columns and rows.

Example: Employee, Department..,

Attribute

An attribute is a specification that defined a property an object, element, or file. An attribute of an object usually consists of a name and a value; of an element, a type or class name; of a file, a name and extension.

Example: EmployeeName, EmployeeAge, DepartmentName..,

Field

A field is an attribute of a table that is designed for specific information about each record/row in the table.

Example: EmployeeName, EmployeeAge, DepartmentName..,

Column

A column is a field in a table that maintains specific field information about each record/row in the table.

Example: EmployeeName, EmployeeAge, DepartmentName..,

Row

Row is also called as a record or tuples of a table.

Data Type

A data type in a programming language is a set of data with values having predefined characteristics.

Examples: integer, floating point unit number, character, string, and binary etc..,

NULL

NULL value is a field with no value (Unknown data, OR Not applicable OR Data not given) 

EmployeeID	EmployeeName	Gender	BirthDate	Salary	Detail
1	Krishnan	M	4/4/1974	30000.00	Krishnan Details
2	Raman	M	12/31/1974	29000.00	Raman Details
3	Durga	F	10/2/1980	25000.00	Durga Details
4	Easwari	F	10/12/1990	NULL	Parvathi Details

Index

An Index is a data structure that improves the speed/fast of data retrieval on a database table.

View

A View in SQL is a logical subset of data from one or more tables.

Synonym

 A Synonym is an alias for a database object. (table, view, procedure, function, etc..)

Cursor

A Cursor is a database object to retrieve data from a result set one row at a time. 

Stored Procedure

A Stored Procedure is a set of Structured Query Language (SQL) statements with an assigned name that's stored in the database in compiled form so that it can be shared by a number of programs.

Function

A Function is same as a stored procedure that must return a value.

Trigger

A Trigger is a special kind of stored procedure that automatically executes when an event occurs in the database server.

Constraints

Constraints are the rules enforced on data columns on a table which ensures the accuracy and reliability/maintain the integrity of the data in the database.

Integrity

Integrity ensures the accuracy and reliability of the data in the database.

Normalization

Database normalization, or normalization, is the process of organizing the columns (attributes) and tables (relations) of a relational database to reduce data redundancy and improve data integrity.

Entity Relationship Model

Entity Relationship Model is a logical relationship of entities (or objects) in order to create a database.

Entity Relationship Diagram (ER Diagram) 

Entity Relationship Diagram is a graphical representation of logical relationship among entities (tables) in the database.