SQL DDL Commands Presentation Summary

Key Topics Covered

SQL Sub-languages

• Data Definition Language (DDL)
  • Focus of presentation: Truncate, Drop, and Rename commands.
• Data Manipulation Language (DML)
• Data Control Language (DCL)
• Transaction Control Language (TCL)

Truncate Command

• Purpose: Remove all rows from a table.
• Syntax: TRUNCATE TABLE <table_name>;
  • Example: TRUNCATE TABLE student;
• Characteristics:
  • Removes all table data, retains the schema.
  • Cannot be rolled back due to auto-commit nature of DDL commands.
• Comparison with Delete Command:
  • Truncate is faster and is a DDL command.
  • Deletes all rows from a table without retaining the schema.

Drop Command

• Purpose: Completely removes a table, including schema and data.
• Syntax: DROP TABLE <table_name>;
  • Example: DROP TABLE student;
• Characteristics:
  • Deletes table and its structure from memory.
  • DDL command, auto-committed, cannot be rolled back.

Rename Command

• Purpose: Change the name of a table.
• Syntax: RENAME <old_table_name> TO <new_table_name>;
  • Example: RENAME student TO student_info;
• Characteristics:
  • Structure of the table remains unchanged except for the name.
  • DDL command, operates on table structure.

Overview of Completed DDL Commands

• Creation and modification of tables (create, alter).
• Removal of data (truncate) versus data and structure (drop).
• Modification of table identity (rename).

Session Summary

• Comprehensive understanding of DDL commands: Create, Alter, Truncate, Drop, Rename.
• Practical examples and explanations provided.
• Future hands-on session to cover renaming columns.

Conclusion

• Presentation and session were informative.
• Engagement appreciated.

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