1. A computer-implemented method for associating information related to an entity stored in a secondary data store with information related to the entity stored in a primary data store, the method comprising: identifying a first entry in a primary data store that contains information related to an entity; receiving a request to associate a second entry in a secondary data store with the identified first entry in the primary data store; identifying information in the secondary data store, wherein the identified information identifies the second entry in the secondary data store; and associating the identified information of the second entry with the first entry in the primary data store by storing the identified information of the second entry in the primary data store, so that the first and second entries from the primary and secondary data store are viewable together without modifying the secondary data store, and without creating intermediate copies of the first and second entries in a merged data store.