Crosswalk
A 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.
Crosswalks are rarely one to one. When one old code splits into several new ones, the table alone cannot say which applies to a given row, and that has to be decided from other fields.
Where it comes up
- Codes without a lookupA column holds short codes such as 3, A, or XR, and the table that says what each code means is not in the file.
- Categories that changed meaningA label stays the same across the file, but what it covers was redefined partway through.
- The same entity in two systemsOne person or organization exists in two systems under different identifiers, with nothing linking the records.
See also
- MappingA 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.
- Lookup tableA table that translates codes into their meanings or one set of values into another, such as state abbreviations to state names.
- Reference dataThe agreed lists of permitted values that other data is classified by, such as country codes, currency codes, and order statuses.