+ * Address book in a database backend
+ *
+ * Backend for personal/shared address book stored in a database,
+ * accessed using the DB-classes in PEAR.
+ *
+ * IMPORTANT: The PEAR modules must be in the include path
+ * for this class to work.
+ *
+ * An array with the following elements must be passed to
+ * the class constructor (elements marked ? are optional):
+ * <pre>
+ * dsn => database DNS (see PEAR for syntax)
+ * table => table to store addresses in (must exist)
+ * owner => current user (owner of address data)
+ * ? name => name of address book
+ * ? writeable => set writeable flag (true/false)
+ * ? listing => enable/disable listing
+ * </pre>
+ * The table used should have the following columns:
+ * owner, nickname, firstname, lastname, email, label
+ * The pair (owner,nickname) should be unique (primary key).
+ *
+ * NOTE. This class should not be used directly. Use the
+ * "AddressBook" class instead.