Step 1 : Get the Foreign Key Name.
SHOW CREATE TABLE tableName;
Note the name of Foreign key (which is mostly auto generated) output will look something like
CONSTRAINT `FK4C5B93445F11A0B7` F...
mysql -h host.address.for.rds.server -u rdsusername -p rdsdatabase < backupfile.sql
host.address.for.rds.server = this will be what is referred to as the "end point" in your RDS descripti...