Presentation on SQL Data Manipulation Language (DML)

Introduction

• Focus on SQL's second sublanguage: DML
• Overview of SQL sublanguages:
  • Data Definition Language (DDL)
  • Data Manipulation Language (DML)
  • Data Control Language (DCL)
  • Transaction Control Language (TCL)

DML Overview

• Directly deals with the data in tables
• Key DML Commands:
  • Insert: Adds new rows to the table
  • Update: Modifies existing rows
  • Delete: Removes rows
  • Select: Retrieves data (sometimes categorized separately as Data Query Language - DQL)

DDL vs. DML

• DDL Commands: Auto-committed and affect table structure (Create, Alter, Drop, etc.)
• DML Commands: Not auto-committed; require explicit save (commit transactions)

Insert Command

• Used to insert new records into a table
• Syntax:

  INSERT INTO table_name (column1, column2, ...) VALUES (value1, value2, ...);
  

• Example:

  INSERT INTO student (ID, name) VALUES (101, 'Neso Academy');
  

Update Command

• Used to modify existing records
• Syntax:

  UPDATE table_name SET column1 = value1, column2 = value2, ... WHERE condition;
  

• Example:

  UPDATE student SET name = 'Sujit Singh' WHERE ID = 101;
  

Important Considerations

• Conditions: Be careful when specifying WHERE conditions to avoid incorrect updates
• Primary Keys: Prefer using primary key attributes for conditions to ensure specific row updates
• Example of cautious condition use:

  UPDATE student SET ID = 101 WHERE ID > 1;
  

Conclusion

• Presented details on insert and update commands in DML
• Stressed caution with update conditions
• Next session: Focus on delete and select DML commands

Closing

• Encouragement for further learning
• Acknowledgement of informative content

[Music] 🎵