Abstract: The present invention provides a method for performing transactions on data entities in a database and a transactional database. The database comprises an ordered set of data stores with at least one static data store, wherein said static data store uses an index structure based on a non-updatable representation of an ordered set of integers according to the principle of compressed inverted indices. The method allows to generate a modifiable data store when the performed transaction comprises an insert, update or delete operation, to execute operations of the transaction on the ordered set being present at the time when the transaction has been started and, if present, on the modifiable data store and to convert data stores to a new static data store, The insert, update or delete operation are executed on the modifiable data store which is the only data store modifiable for the transaction.

Abstract: A method and system is provided for efficient journaling and management of electronic messages, wherein a copy of a first message sent from or received on a mail server is received, the copy of the first message is then recorded by a journal service, wherein the journal service comprises determining whether the first message contains an identification for which a second message has already been recorded and adding only metadata of the first message to the metadata of the second message when for the identical identification the second message has already been recorded.

Abstract: A method is provided for the storage-efficient management of electronic messages, wherein a message that is to be managed is first received, the message is decomposed into a basic structure and file attachments contained in the message, a unique identification value is calculated for each file attachment, the file attachment is stored as a file with a respective identification value for which no file exists in the storage, or a reference counter of the file attachment for whose identification value a file already exists in the storage, is incremented, and the basic structure with references to the files in the storage, which references correspond to the file attachments originally contained in the message, is stored.