If no database has been selected, specifying a database qualifier is necessary.

This question asks about working with databases in MySQL.
Imagine a library with many different bookshelves. Each bookshelf represents a different database.
When you want to find a specific book, you need to know which bookshelf it's on. Similarly, in MySQL, you need to tell the system which database you want to use.
If you haven't selected a database (like not knowing which bookshelf to look in), you need to specify the database name when you work with tables or data.

So, the answer is True.