Introduction to SQL | SQL Tutorial for Beginners | G C Reddy |

Описание

https://www.gcreddy.com/2021/08/introduction-to-sql.html
Structured Query Language Commands and Operations, What is SQL?, Purpose of SQL, Who Should Learn SQL?, Subsets of SQL, Data Definition Language, Data Manipulation Language and Data Control Language. SQL Introduction for Database Developers, Database Administrators and Database Testers.
Introduction to SQL -Structured Query Language

1 What is SQL?
2 Purpose of SQL
3 Who should learn SQL?
4 What are the subsets of SQL?
5 Data Definition Language
6 Data Manipulation Language
7 Data Control Language
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1 What is SQL?

• SQL stands for Structured Query Language
• SQL was initially developed at IBM in 1970s
• SQL is the standard language to communicate with relational database management systems like Oracle, MS Access, MS SQL Server, MySQL, DB2, Sybase Etc...
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2 Purpose of SQL

• SQL is used to Create New Databases
• SQL is used to Create New Tables in a Database
• SQL is used to Insert records in a Database
• SQL is used to Update records in a Database
• SQL is used to Delete records in a Database
• SQL is used to Retrieve data from a Database
• SQL is used to execute queries against a Database
• SQL can set permissions on tables, procedures and views
• SQL is used to Create stored procedures in a Database
• SQL is used to Create views in a Database
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3 Who should learn SQL?

i Database Developers

• Design and deploy Database table structures, forms, reports and queries etc...

ii Database Administrators (DBA

• Keeping databases up to date and managing database access
• Writing Reports, documentation and operating manuals

iii Database Testers

• Verify Data Integrity
• Verify Data Manipulations (Add, Update and Delete
• Verify Data comparisons
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4 What are the subsets of SQL?

SQL Commands can be classified in to groups based on their nature, they are,

i Data Definition Language
ii Data Manipulation Language
iii Data Control Language
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5 Data Definition Language

Important Commands and Operations in Data Definition Language

i Create: To create databases and database objects

ii Alter: To modify existing database objects

iii Drop: To drop databases and databases objects

iv Truncate: To remove all records from a table

v Rename: To rename database objects
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6 Data Manipulation Language

Important Commands and Operations in Data Manipulation Language

i Select: To select specific data from a database

ii Insert: To insert new records in a table

iii Update: To update existing records

iv Delete: To delete existing records from a table
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7 Data Control Language

Important Commands and Operations in Data Control Language

i Grant: To provide access on the Database objects to the users

ii Revoke: to remove user access rights to the database objects

iii Deny: To deny permissions to users.
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