Which of the following is not a DDL command?

Question

Accepted Answer

The correct option is (4):
The correct option is **UPDATE** because it belongs to the Data Manipulation Language (DML) subset of SQL, not the Data Definition Language (DDL). DDL commands are specifically designed to define or modify the *structure* or *schema* of database objects, such as tables and indexes. In contrast, the **UPDATE** command is used to modify the *actual data* stored within the existing structure of a table, such as changing a specific value in one or more rows based on a condition. Since its purpose is to manipulate the content of the data rather than change the database blueprint itself, it is classified as DML, which correctly identifies it as the command that is *not* a DDL command.

The incorrect option is (1):
**TRUNCATE** is classified as a DDL command. Although it removes data like the DML statement DELETE, its mechanism is fundamentally structural. **TRUNCATE** removes all rows from a table by quickly deallocating the data pages and space used by the table, which is an operation on the table object's structure. It typically cannot be individually rolled back (it often performs an implicit commit) and resets the table's identity columns (like auto-increment counters). These structural and non-transactional characteristics clearly align it with Data Definition Language operations.

The incorrect option is (2):
**ALTER** is a core DDL command. Its sole purpose is to change the *structure* or *definition* of an existing database object. For example, students use **ALTER TABLE** to add new columns, drop existing columns, change a column's data type, or add/remove constraints and keys. Because it modifies the metadata and the blueprint of the object itself, rather than manipulating the data contained within the object, it is a definitive Data Definition Language command.

The incorrect option is (3):
**CREATE** is the foundational command of the DDL. This command is used to initially define and construct new database objects from scratch, such as creating a new **TABLE**, a new **INDEX**, a new **VIEW**, or an entire **DATABASE**. Because its function is to formally define the schema or the structure of the data organization, it is the primary and most obvious example of a Data Definition Language command. DDL is all about the creation and management of the object's definition.