134 136 cached data change objects 138 140 and associated cookies 142 144 in this example the progress connector 118 is implemented as an out connector and represented as one of the connector metadata 132 134 136 thus connector metadata except the progress connector 118 includes for each in connector and out connector a library and object name 146 connector settings 148 and object metadata 150 152 each object metadata includes a source object name 154 a target object name 156 and attribute metadata 158 attribute metadata 158 includes a source attribute name 160 a target attribute name 162 and an indication whether the attribute metadata 158 is a primary key 164 changes updates in the xml configuration file 112 are reflected in metadata 132 134 136 further the relationships between data formatted for the source store and target store are indicated in the example of fig4 b with the linking arrows 166 168 170 thus as can be seen the udc 110 is self describing such that the data objects 138 140 are represented within the synchronizer 102 as normalized data independent of object and attribute naming requirements for either the source store 104 and or the target store 106 advantageously in connector 114 and out connector s 116 may have any suitable configuration for any selected data format fig5 shows an example of a method of self selecting and starting the active synchronizer e g 102 in fig1 first in step 180 the active synchronizer 102 dynamically instantiates the connectors using the library name and object name of the connector from the xml configuration file 112.