When a database is imported, two structures are created for each table in the following categories (each represented by a folder):
Tables - The structure which contains a loop representing the rows of the table. You use this structure directly in a map. You can also open this structure in the structure editor and view the database data using the Show Document button or Show Sample menu item.
If you are reading from or writing to the database, this is the one to use. When reading, use the DatabaseSelect function in the Row element. When writing use either the DatabaseInsert or DatabaseUpdate function in the Row element.
Single Row Tables - The structure which defines the columns of the table. The Tables structure inherits from this one. In addition, each of these structures has a Database representation which defines the properties associated with that table, like primary key and automatic ID generation. Finally, this is also used to construct joined tables.
Joined Tables - This is initially empty and is where tables that represent a join are placed by the join wizard.