Mgo（mongo for go）支持物化路径吗？

Question

With BSON and Mgo(rich mongodb driver for go), how would one approach implementing materialized paths?

Materialized paths are documented here on the mongo docs. Materialized paths are designed to provide a tree-like structure for multiple levels of nested data.

With plain javascript, the command are as follows (from the documentation):

db.categories.insert( { _id: "Books", path: null } )
db.categories.insert( { _id: "Programming", path: ",Books," } )
db.categories.insert( { _id: "Databases", path: ",Books,Programming," } )
db.categories.insert( { _id: "Languages", path: ",Books,Programming," } )

Created collection 'categories' with the following entries

Books > Programming > Databases
Books > Programming > Languages

And can be queried using:

db.categories.find( { path: /,Programming,/ } )

Will find the two entries which are both decendants of programming.

How do I implement this using Mgo and BSON?

There is no such documentation in the Mgo docs. I have tried attempts such as

result := []bson.M{}
database.C("categories").Find(bson.M{"path": "/,Programming,/"}).All(&result)
fmt.Println(result)

Only to return an empty array []

Any gophers and mongo lovers to enlighten me here?

Thanks!

Answer 1

Checkout this part in mgo/bson documentation: http://godoc.org/labix.org/v2/mgo/bson#RegEx

It should probably look like this

database.C("categories").Find(bson.M{"path": &bson.RegEx{Pattern: ",Programming,", Options: "i"}}).All(&result)