Обсуждение: MongoDB FDW Problem.

My best for all in this list.

i'm trying to use FDW for MongoDB using PostgreSQL 9.4 using pgdg yum 
repo:   yum install postgresql94-server postgresql94-contrib mongo_fdw94
My S.O. is CentOS 9.7 64bits

All is ok with Postgres.  I can create extension, foreign server and 
foreign table.
My problem is when the "columns" of the MongoDB collection are a 
document or array.   In my Foreign Table, I have only null values 
returned in selects.
All of others columns returns its values with no problem.
Can any help or advise me about this?

Thanks a lot!
Lucio - Rio de Janeiro - Brazil

Please see below some info:

On mongo i have this on collection:

{  "_id" : ObjectId("56ae3a5c2e277c04c77beec7"),  "address" : {    "building" : "469",    "coord" : [-73.961704, 40.662942],    "street" : "Flatbush Avenue",    "zipcode" : "11225"  },  "borough" : "Brooklyn",  "cuisine" : "Hamburgers",  "grades" : [{      "date" : ISODate("2014-12-30T00:00:00Z"),      "grade" : "A",      "score" : 8    }, {      "date" : ISODate("2014-07-01T00:00:00Z"),      "grade" : "B",      "score" : 23    }, {      "date" : ISODate("2013-04-30T00:00:00Z"),      "grade" : "A",      "score" : 12    }, {      "date" : ISODate("2012-05-08T00:00:00Z"),      "grade" : "A",      "score" : 12    }],  "name" : "Wendy'S",  "restaurant_id" : "30112340"
}

On PostgreSQL I have this:

"_id"    "address"    "borough"    "cuisine"    "grades" "name"    
"restaurant_id"
"56ae3a5c2e277c04c77beec7"  <null>  "Brooklyn" "Hamburgers"  <null>   
"Wendy'S"    "30112340"

CREATE FOREIGN TABLE mongo_fdw.restaurants (  _id NAME NOT NULL,  address JSON,  borough VARCHAR,  cuisine VARCHAR,  grades VARCHAR, --> errors happens if I put json here  name VARCHAR,  restaurant_id VARCHAR
)
SERVER mongo_server
OPTIONS (  database 'test',  collection 'restaurants');

2016-02-02 20:10 GMT-02:00  <postgresql@vorio.com.br>:
> My best for all in this list.
>
> i'm trying to use FDW for MongoDB using PostgreSQL 9.4 using pgdg yum
> repo:   yum install postgresql94-server postgresql94-contrib mongo_fdw94
> My S.O. is CentOS 9.7 64bits
>
> All is ok with Postgres.  I can create extension, foreign server and
> foreign table.
> My problem is when the "columns" of the MongoDB collection are a
> document or array.   In my Foreign Table, I have only null values
> returned in selects.
> All of others columns returns its values with no problem.
> Can any help or advise me about this?

I don't work with that but It seems that was an
issue [1] that was fixed in mongo_fdw master [2].

I think that you can follow the instructions here [3]
and contact the extension’s authors to get some
more precise information.

[1] https://github.com/EnterpriseDB/mongo_fdw/issues/32
[2] https://github.com/EnterpriseDB/mongo_fdw/commit/632e78c303024d3a3cbd1a1c1fc5c27784260836
[3] https://github.com/EnterpriseDB/mongo_fdw#contributing

[]s
--
Dickson S. Guedes
mail/xmpp: guedes@guedesoft.net - skype: guediz
http://github.com/guedes - http://guedesoft.net
http://www.postgresql.org.br