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Friday, July 6, 2018

SQL Overview

SQL Tutorial 2: SQL Overview

SQL (Structured Query Language) is a touchstone linguistic communication for accessing databases.

All Relational Database Management Systems similar MS Access, MS SQL Server, Oracle, Sybase, MySQL, DB2 use SQL every bit touchstone database language.
i) Environment Setup

We tin practise SQL Commands inwards whatsoever Database Management System, Install whatsoever Database Engine similar Oracle, SQL Server, Sybase, MySQL etc... and practice.
ii) SQL Syntax

•  A database contains 1 or to a greater extent than tables. Each tabular array is identified yesteryear a name, Tables incorporate records (rows) with data.

•  Most of the actions nosotros postulate to perform on a database are done amongst SQL statements.

•  SQL keywords are NOT illustration sensitive: select is the same every bit SELECT

•  All the SQL statements rootage amongst whatsoever of the keywords similar SELECT, INSERT, UPDATE, DELETE etc...and all the statements terminate amongst a semicolon (;), semicolon is the touchstone agency to sort out SQL Statements.
iii) SQL Data Types

 A information type defines what variety of value a column tin contain, nosotros bring to usage information types piece creating database tables, select a item information type for a tabular array column based on our requirement.


Character Data Types,
Numeric Data Types,
Date as well as Time Data Types Etc...

Note: Data Types vary from One Database Management System to another
iv) Operators

Operators are used to perform Arithmetic, Comparison as well as Logical Operations.

Categories of Operators inwards SQL

1) Arithmetic Operators
2) Comparison Operators
3) Logical Operators
v) SQL Functions

SQL has many built-in functions for performing processing on data.

Categories of Built-in Functions inwards SQL

1) Aggregate Functions
2) String Functions
3) Date Functions Etc...
vi) Data definition Language

The Data definition Language (DDL) is used to do as well as destroy databases as well as database objects. 

Important Operations

 Create Database
 Use Database (Specify the Database you lot wishing to piece of employment amongst inside your DBMS.)
 Alter Database
 Drop Table, Drop Database
vii) Data Manipulation Language

The Data Manipulation Language (DML) is used to insert, yell back as well as modification database information.

Important Operations

 Insert Records to an existing Table
 Retrieve the specific information from an operational database. 
 Modify information contained inside a Table.
 Delete information contained inside a Table.
viii) Data Control Language

The Data Control Language (DCL) allows database administrators to configure safety access to relational databases.

Important Operations

• Provide access on the Database objects to the Users
• Remove User access rights to the Database Objects
• Deny Permissions to Users.
ix) SQL SELECT Statement

The SELECT contention is used to select information from a database.

 General Selection
 Conditional Selection Etc...
(We usage clauses, Operators as well as keywords...)
x) SQL Joins

The SQL Joins clause is used to combine records from ii or to a greater extent than tables inwards a database. 

Different SQL Joins:

1) Inner Join
2) Left Join
3) Right Join
4) Full Join
Popular Database Management Systems

1) Oracle

Oracle database is a relational database administration organization (RDBMS) developed yesteryear Oracle Corporation. 

Important Oracle editions are, 

i) Enterprise Edition: Offers all features, including superior performance as well as security.

ii) Standard Edition: Contains base of operations functionality for users.

iii) Express Edition: The lightweight, complimentary as well as express Windows as well as Linux edition

iv) Oracle Lite: For mobile devices
2) Microsoft SQL Server

Microsoft SQL Server is a relational database administration organization developed yesteryear Microsoft.

Important Microsoft SQL Server editions are, 

i) Datacenter: SQL Server 2008 R2 Datacenter is a full-featured edition of SQL Server.

ii) Enterprise: SQL Server Enterprise Edition includes both the essence database engine as well as improver services.

iii) Standard: SQL Server Standard edition includes the essence database engine, along amongst the stand-alone services.

iv) Web: SQL Server Web Edition is for Web hosting.

v) Workgroup: SQL Server Workgroup Edition includes the essence database functionality only.
3) MySQL

MySQL is an Open Source Relational SQL database administration organization used for developing web-based software applications.

Important MySQL Editions are, 

i) Standard Edition: Standard Edition enables us to deliver high-performance as well as scalable Online Transaction Processing (OLTP) applications.

ii) Enterprise Edition: Enterprise Edition includes the almost comprehensive fix of advanced features as well as administration tools.

iii) Cluster Carrier Grade Edition: Cluster enables users to encounter the database challenges of side yesteryear side generation web, cloud, as well as communications services amongst uncompromising scalability, uptime as well as agility.
4) PostgreSQL

PostgreSQL is a powerful, opened upward source database administration system. It runs on all major operating systems, including Linux, UNIX, Mac OS X, Solaris, as well as MS Windows.
5) MS Access

Microsoft Access is bundled every bit part of the Microsoft Office suite. It is simply available on the PC version. It is a desktop database organization because its functions are intended to live on run from a unmarried computer.
SQL Tutorial 1: Introduction to SQL


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