Selecting data for synchronization

Abstract

A method for selecting a data set to be synchronized from databases of a data system, in which system metadata illustrating the relationships between data units of the data system are stored for the selection of the data set to be synchronized. The metadata comprises at least information on the relevance between the data units. When a first data set is to be synchronized, metadata associated with at least one initial data unit of the first data set is retrieved. Next, a second data set, which according to at least one metadata element comprises a data unit of maximum relevance to the initial data unit, is selected for synchronization.

What is claimed is:  
     
         1 . A method for selecting a data set to be synchronized from databases of a data system, the method comprising: 
 maintaining in the data system metadata representing the relationships between data units for the purpose of selecting the data set to be synchronized, the metadata comprising at least information on the relevance of the data units with regard to one another;    retrieving metadata associated with at least one initial data unit of a first data set in response to a need to synchronize the first data set;    selecting a second data set for synchronization, the data set comprising at least one data unit which, on the basis of said metadata, is most relevant to the initial data unit.    
     
     
         2 . A method according to  claim 1 , further comprising: 
 selecting one data unit at a time into the second data set in the order of relevance;    checking the size of the second data set after a new data unit has been added; and    initiating synchronization with the second data set in response to a predetermined size limit having been reached.    
     
     
         3 . A method according to  claim 1 , wherein 
 only data units which exceed one or more predetermined exclusion criteria, such as the minimum relevance value, are selected into the second data set.    
     
     
         4 . A method according to  claim 1 , wherein 
 said metadata further includes utility information representing the utility provided by at least one data unit associated with an initial data unit in said metadata, either directly or through other data units, provided that the initial data unit has been selected.    
     
     
         5 . A method according to  claim 4 , further comprising: 
 determining numerical values representing relevance probabilities and utilities between the initial data units and other data units for the metadata;    forming links between the data units in said metadata, the links being associated with the numerical values of at least relevance and utility;    multiplying the relevance values of the links along at least one path originating from the initial data set and leading to other data units;    selecting the utility value of the last link leading to another, separate data unit to be used as the utility of that data unit;    calculating an expected gained utility value for each one of the other data units by multiplying the utility value by the relevance value;    comparing the expected gained utility values of the different data units; and    selecting at least one data unit with the highest expected gained utility value into the second data set.    
     
     
         6 . A method according to  claim 1 , further comprising: 
 updating said metadata on the basis of user actions.    
     
     
         7 . A method according to  claim 1 , wherein 
 application-specific metadata are added to the data system in response to the adoption of a new application; and    the metadata associated with the at least one initial data unit are retrieved as required by the application.    
     
     
         8 . A method according to  claim 1 , wherein 
 situation-specific metadata for at least two different synchronization situations are determined into the data system; and    the metadata associated with the at least one data unit are selected as required by the synchronization situation.    
     
     
         9 . A method according to  claim 1 , further comprising: 
 determining the expected gained utility value for initial data units in the first data set by experimentally adding initial data units, one by one, to the first data set, and    selecting into the second data set one or more initial data units the adding of which provides the highest expected gained utility value.    
     
     
         10 . A method according to  claim 1 , wherein 
 the data system includes at least one synchronization client device and synchronization server;    a request for selecting a data set in accordance with the method is sent from the synchronization client device to the synchronization server during the initialization of the synchronization session;    second data sets are selected in the synchronization client device and the synchronization server in accordance with the method;    the modifications that have taken place in the second data set since the last synchronization session are sent from the synchronization client device to the synchronization server; and    the modifications that have taken place in the second data set since the last synchronization session are sent from the synchronization server to the synchronization client device.    
     
     
         11 . A synchronization system comprising: 
 means for synchronizing the data of at least two databases;    means for maintaining metadata representing the relationships between data units, the metadata comprising at least information on the relevance of the data units with regard to one another;    means for retrieving the metadata associated with at least one initial data unit of a first data set in response to a need to synchronize the first data set;    means for selecting a second data set for synchronization, the second data set comprising at least one data unit which, on the basis of the metadata, is most relevant to the initial data unit.    
     
     
         12 . A synchronization system according to  claim 11 , further comprising: 
 means for selecting one data unit at a time into the second data set in the order of relevance;    means for checking the size of the second data set after a new data unit has been added; and    means for initiating synchronization with the second data set in response to a predetermined size having been reached.    
     
     
         13 . A synchronization system according to  claim 11 , wherein 
 said metadata also contains utility information representing the utility provided by at least one data unit associated with an initial data unit in said metadata, either directly or through other data units, provided that the initial data unit has been selected.    
     
     
         14 . A synchronization system according to  claim 11 , further comprising: 
 means for taking application-specific metadata in use in response to the adoption of a new application; and    means for retrieving the metadata associated with at least one initial data unit as required by the application.    
     
     
         15 . A synchronization device comprising: 
 means for sending modifications made to a data set to be synchronized of at least one database to at least one second party involved in the synchronization:    means for storing metadata representing the relationships between the data units, the metadata comprising at least information on the relevance of the data units with regard to one another;    means for retrieving metadata associated with at least one initial data unit of a first data set in response to a need to synchronize the first data set;    means for selecting a second data set for synchronization, the second data set comprising at least one data unit which, on the basis of the metadata, is most relevant to the initial data unit.    
     
     
         16 . A synchronization device according to  claim 15 , wherein 
 the metadata also contains utility information representing the utility provided by the at least one data unit associated with an initial data unit in said metadata, either directly or through other data units, provided that the initial data unit has been selected.    
     
     
         17 . A computer software product for controlling a synchronization device, comprising program code which, when executed in the synchronization device, causes the synchronization device to 
 store metadata representing the relationships between data units for the selection of a data set to be synchronized, the metadata comprising at least information on the relevance of the data units with regard to one another;    retrieve metadata associated with at least one initial data unit of a first data set in response to a need to synchronize the first data set;    select a second data set for synchronization, the second data set comprising at least one data unit which, on the basis of the metadata, is most relevant to the initial data unit.    
     
     
         18 . A computer software product according to  claim 17 , wherein 
 the metadata also comprises utility information representing the utility provided by the at least one data unit associated with an initial data unit in said metadata, either directly or through other data units, provided that the initial data unit has been selected.