Table names have all lowercase letters and underscores between words, also all table names need to be plural, e.g. invoice_items, orders.

If the table name contains serveral words, only the last one should be plural:

applications
application_functions
application_function_roles

Field names will be lowercase, generally singular case, and words are separated by underscores, e.g. order_amount, first_name

The foreign key is named with the singular version of the target table name with _id appended to it, e.g. order_id in the items table where we have items linked to the orders table.

Tables used to join two tables in a many to many relationship is named using the table names they link, with the table names in alphabetical order, for example items_orders.