1. A method for updating a fragment of an electronic document having a prescribed hierarchical structure based on XML, wherein said electronic document is stored in a storage device of a client device in a broadcasting system and said fragment is a portion in the prescribed hierarchical structure of the electronic document and describes metadata related to a broadcasting program identified by a program identifier, and wherein a fragment identification identifies said fragment in the prescribed hierarchical structure of the electronic document, the method comprising: sending a request for an updated version of said fragment from the client device to a server device of a content provider; in response to said request, receiving an update document at said client from said content provider, the update document including an invalid element indicating that said fragment in the electronic document is invalid, wherein the invalid element in the update document identifies said fragment in the prescribed hierarchical structure by using the fragment identification of the fragment in the electronic document; using the fragment identification in the invalid element to identify the invalid fragment in the electronic document stored in the client device; and deleting from the electronic document stored in the client device said fragment that is indicated as being invalid by the invalid element in the received update document.
1. A method for updating a fragment of an electronic document having a prescribed hierarchical structure based on XML, wherein said electronic document is stored in a storage device of a client device in a broadcasting system and said fragment is a portion in the prescribed hierarchical structure of the electronic document and describes metadata related to a broadcasting program identified by a program identifier, and wherein a fragment identification identifies said fragment in the prescribed hierarchical structure of the electronic document, the method comprising: sending a request for an updated version of said fragment from the client device to a server device of a content provider; in response to said request, receiving an update document at said client from said content provider, the update document including an invalid element indicating that said fragment in the electronic document is invalid, wherein the invalid element in the update document identifies said fragment in the prescribed hierarchical structure by using the fragment identification of the fragment in the electronic document; using the fragment identification in the invalid element to identify the invalid fragment in the electronic document stored in the client device; and deleting from the electronic document stored in the client device said fragment that is indicated as being invalid by the invalid element in the received update document. 2. The method of claim 1 , wherein said fragment is previously received from said server device of the content provider and stored in the storage device of said client device.