data dictionary

I also see quite a dichotomy between starting a data dictionary as an aid to building a (greenfields) data source, and documenting an already-existing system A data dictionary is, at its most simple, a mapping of data elements your organization stores, where it stores them, and what each element means. While it’s simple to describe, it’s a bit more complicated and time-consuming to implement. Another reason for a data dictionary is that you need to determine authoritative sources for your data elements when you need systems to interact. Defining Data Elements for the Data Dictionary