SQL Data Control Language (DCL) Presentation

Introduction

• Focus on SQL's sublanguage: Data Control Language (DCL).
• SQL consists of four sublanguages:
  1. Data Definition Language (DDL)
  2. Data Manipulation Language (DML)
  3. Data Control Language (DCL)
  4. Transaction Control Language

Three-Tier Architecture

• Predominant architecture for traditional client-server applications.
• Organizes applications into three logical and physical computing tiers:
  1. Presentation Tier: User interaction level with GUI access.
  2. Application Tier: Processes data and implements business logic.
  3. Database Tier: Stores and manages data with DBMS.

Advantages

• Separate development teams can work on each tier independently.
• Allows scaling and updates without disrupting other tiers.

Presentation Tier

• Developed using tools like HTML, CSS, JavaScript.
• Front end system: ATM interfaces and internet banking sites.

Application Tier

• Middle tier: Where business logic and rules are processed.
• Tools used include Python, Perl, Java, PHP, Ruby, etc.

Database Tier

• Storage and retrieval of data using DBMS.
• Tools include MySQL, MariaDB, DB2, Informix, Microsoft SQL Server.

Data Control Language (DCL)

• Provides authorization – who can access what in the database.
• Key commands: GRANT and REVOKE.

GRANT Command

• Syntax: GRANT privilege_name ON object_name TO user;
• Provides rights or permissions to users.

Examples

• GRANT SELECT ON student TO Rahul;
  • Rahul can execute the select operation on the student table.
• GRANT SELECT, UPDATE ON student TO Rahul;
  • Rahul has select and update privileges on the student table.

REVOKE Command

• Syntax: REVOKE privilege_name ON object_name FROM user;
• Removes specific rights from users.

Example

• REVOKE SELECT, UPDATE ON student FROM Rahul;
  • Rahul can no longer perform select or update operations on the student table.

Conclusion

• Explanation of three-tier architecture.
• DCL commands demonstrated: GRANT and REVOKE.
• Aids in managing database permissions effectively.

Thank you for watching!