In cases where the data used to populate a target field is dependent on some condition, that condition can be applied to the mapping on that target field.

对于要依赖某种条件来使用数据填充目标字段的情况，可以对该目标字段上的映射应用条件。

youdao

Delete the existing mapping to the field ExternalSystemID.

删除已有的到字段ExternalSystemID的映射。

youdao

It's then trivial to add another field mapping for the ISBN of the book.

然后为书的IS BN添加另一个字段映射。

youdao

All this geographic mania amuses the de facto father of the mapping field: Jack Dangermond, founder and president of Environmental Systems Research Institute, the 37-year-old firm that is the Microsoft of mapping.

FORBES: Magazine Article

Ebb and Flow deliberately plunged into a lunar mountain in December after mapping the moon's gravity field in unprecedented detail.

NPR: NASA Moon Craft Spots Ebb And Flow Crash Sites

The Department of Agriculture has begun the huge task of re-mapping every field in Northern Ireland.

BBC: Every field in Northern Ireland to be re-mapped