Final answer:
The COPY command can be used to read data from standard i/o devices, table back to CSV, and CSV to table. Therefore, the correct answer is d) all. This command is essential for tasks like data import/export and database backup.
Step-by-step explanation:
The COPY command can be used to read data from:
- a) std i/o devices
- b) table back to CSV
- c) CSV to table
- d) all
In the context of database management, the COPY command is versatile and can perform actions such as reading data from standard input/output (std i/o) devices, copying data from a table back to a CSV file, and copying data from a CSV file into a table. Thus, the correct answer to the question is d) all. The COPY command is particularly useful in situations where bulk data import or export is required and is often used for backup and recovery purposes or for the initial loading of data into a database.