During the go-live migration the client’s legacy system will be closed off prior to the final data extract, new information can’t be entered into Zavanti until the migration is complete. Depending on the volume of data that is migrating the time required to completely migrate and review a full set of data for go-live may extend to a length that is unfeasible to have no staff able to work in any system. To handle this possibility data can be migrated via a delta method, i.e. once the initial mapping is confirmed and post migration functionality tested, the later migration runs will only include data that has been created or records that have been edited in any way. This requires an additional column tracking the date the data was last modified on, often this is taken from the audit functionality in the CHPs previous tenancy management system. A full export of the data will be done by the CHP for each of these ‘delta migrations’ even though only some of the data will be migrated, depending on the ‘modified on’ column in the exported data.
Any new customisations added that need data migrated to them will mean a full migration of that template/entities data is required to update it for all records. Because of this it is important that customisations be finalised before the later delta runs begin. These delta migrations will be run more and more regularly as the go live migration approached to reduce the volume of data in each run, therefore it is crucial that the export of data from the legacy system is as fast as possible.