Which of the following commands is used to delete all rows and free up space from a table?OptionsALTERDROPTRUNCATEDELETE

Break Down the Problem

1. Identify the purpose of each command in SQL related to data manipulation and management.
2. Determine which command is explicitly used for deleting all rows and freeing up space in a table.

Relevant Concepts

1. ALTER: Typically used to modify the structure of a table, like adding or deleting columns.
2. DROP: Used to completely remove a table and all its data from the database.
3. TRUNCATE: This command removes all rows from a table but does not remove the table itself. It also typically resets any auto-incrementing values and frees up the space used by the table immediately.
4. DELETE: Deletes rows from a table based on a specified condition; however, it does not free up space immediately and can be slower than TRUNCATE.

Analysis and Detail

• ALTER is not relevant as it changes the table structure.
• DROP completely removes the table and its structure, not just the rows.
• DELETE can delete rows but does not reset auto-increment sequences or free all space immediately.
• TRUNCATE is designed specifically to quickly remove all rows from a table while potentially resetting auto-increment values and improving performance since it doesn't log individual row deletions.

Verify and Summarize

Considering the definitions and purposes of each command, the preferred command for deleting all rows and freeing up space efficiently is TRUNCATE.

Final Answer

TRUNCATE is the command used to delete all rows and free up space from a table.