清单5向数据库添加了一条赛道和一个地点，由从trails中的location_id列指向locations中的id列的外键管理。

Listing 5 adds a trail and a location to the database, managed with a foreign key pointing from the location_id column in trails to the id column in locations.

youdao

清单5向数据库添加了一条赛道和一个地点，由从trails中的location_id列指向locations中的id列的外键管理。

Listing 5 adds a trail and a location to the database, managed with a foreign key pointing from the location_id column in trails to the id column in locations.

youdao