Business analysis glossary
Field Mapping
What it is
Field mapping documents how each data field in a source system corresponds to a field in a target system, including format conversions, default values and rules for missing data. Each row usually shows the source field, the target field, the data type, a transformation rule and any comment, such as what to do when the source is blank.
Why it matters
Integrations fail on small mismatches such as date formats or code values. A mapping table gives developers and testers an exact, reviewable specification. Business users review it too, because some mapping choices, like merging two status values into one, change the meaning of reports.
Example
Migrating customers into a new system at Cedar Credit Union, the mapping shows the old field DOB in format DD/MM/YYYY becomes date_of_birth in ISO format, and the old status code "A" becomes "active". A reviewer can scan the table, spot the date format change and ask the developer to confirm how a blank value is converted.