Which of the following is true about DDL operations?

The assertion that some DDL (Data Definition Language) operations are metadata-only operations is accurate. DDL encompasses commands like CREATE, ALTER, and DROP, which define or modify database structures rather than the data within them. Operations such as creating a table or altering a schema primarily focus on the metadata, which defines how data is organized, structured, and managed. For instance, the command to create a table updates the database's state by adding new table metadata, while the actual data entries are managed separately through DML (Data Manipulation Language) operations like INSERT or UPDATE.

The other statements do not hold true. While DDL operations fundamentally deal with the structure of the database, they do not always involve data retrieval. Not all DDL commands create new tables; for example, an ALTER command can modify existing structures without creating new ones, and DDL operations do not delete rows from tables—that action is specifically managed through DML commands.