[轉]database.yml &, <<, *

http://stackoverflow.com/questions/6651275/what-do-the-mean-in-this-database-yml-file

The & marks an alias for the node (in your example &defaultaliases the development node as “default”)

• references the aliased node with the name “default”.

«: inserts the content of that node.

test: &test «: *default

default_env: «: *production