Abstract: An e-mail application program operating on a client stores e-mail records in a hierarchical database. The client is linked to a server that stores e-mail records in a flat database. The e-mail records stored in the hierarchical database are mapped to the e-mail records stored in the flat database and vice versa. The mapped e-mail records are then stored in a mapping table.

Abstract: In one exemplary implementation, a client receives a record from a server. The record has a server identification key that uniquely identifies the record from any other records. If the record is viewable by a user in one or more folders, there are corresponding one or more associated references that indicate which one of the one or more folders the record is viewable For each of the one or more associated references, one or more new records identical to the received record are created. One or more client identification keys are assigned to the one or more new client records; wherein each of the one or more client identification keys uniquely identifies the one or more new client records. Each of the one or more new client records are synchronized to the record received from the server by mapping the one or more client identification keys to the server identification key.

Abstract: A client device accesses an on-line version of an address book when the client device is connected to a server and alternatively accesses an off-line version of the address book in lieu of the on-line version of the address book when the client device is not connected to the server. The on-line version of the address book and the off-line version of the address book are stored in disparate formats. The client device is able to seamlessly switch from the on-line version to the offline version, and vice versa, by monitoring whether the client is connected to the server.

Abstract: In one exemplary implementation, a client receives a record from a server. The record has a server identification key that uniquely identifies the record from any other records. If the record is viewable by a user in one or more folders, there are corresponding one or more associated references that indicate which one of the one or more folders the record is viewable For each of the one or more associated references, one or more new records identical to the received record are created. One or more client identification keys are assigned to the one or more new client records; wherein each of the one or more client identification keys uniquely identifies the one or more new client records. Each of the one or more new client records are synchronized to the record received from the server by mapping the one or more client identification keys to the server identification key.