The net change utility is a Java™-based tool that compares new, incoming data to existing data from the same source.
The utility checks incoming records against an existing data set to determine if each incoming record is:
Use the net change utility whenever you have incoming data that repeats data that you already have. For example, if one of the monthly data source feeds is a telephone directory data source, you might want to check for duplicates before loading the new file as most telephone numbers do not change every month.
By eliminating duplicate records to prevent the conversion utility or pipelines from having to process them and can reduce the overall system processing time.
The settings in the configuration file describe runtime parameters essential to comparing records. Settings that define the width of the record, record criteria, and record key must be accurate for the net change utility to be successful. For example, if the total file size is not evenly divisible by the record length plus the padding length, the net change utility displays an error and stops.
The net change utility compares an incoming record set to an existing base record set. It creates a difference file (.dif) that specifies which records represent an add, change, delete, or seen record. the utility creates a merge file (.merge) that overwrites the original base record set and will be used as the next base record set. The net change utility can then send the difference file to the UMF file conversion utility or another UMF generation utility, or if the data source provides the records in UMF format, directly to a pipeline.
Net change utility performs two kinds of comparisons: