Mapping
A stated correspondence between a source and a target. In data preparation it means either which source column feeds which target column, or which source value becomes which standard value, such as Calif. to CA.
A mapping is worth keeping as its own table, separate from the code or formulas that apply it. Then it can be reviewed, corrected, and reused on the next file.
Where it comes up
- Inconsistent category labelsA column meant to hold a few fixed values holds many spellings of them.
- Inconsistent column names across filesFiles that should share one layout name the same column differently, or use the same name for different things.
See also
- CrosswalkA table that pairs each code in one system with its equivalent in another, such as an old product code beside the new one that replaced it.
- Lookup tableA table that translates codes into their meanings or one set of values into another, such as state abbreviations to state names.
- Canonical valueThe one agreed spelling for a thing that can be written several ways, such as VA for Virginia, virginia, and Va.