mongo cheat sheet - various cope snippets for manipulating databases and collections

gistfile1.txt

Increment counter:
  db.analytics.update({"url" : "www.example.com"},{"$inc" : {"pageviews" : 1}})

Adding/Updating a field in a document:
  db.blog.posts.update({"author.name" : "joe"}, {"$set" : {"author.name" : "joe schmoe"}})
  db.positions.update({},{$set:{pos_short_status:"O"}},{upsert:false,multi:true});
  db.clients.update({cli_status:"N"},{$set:{cli_status:"A"}},{upsert:false,multi:true});

Removing a field from a document:
  db.users.update({"name" : "joe"}, ... {"$unset" : {"favorite book" : 1}})

Renaming a field in a collection:
  db.usrGrades.update({},{$rename:{"grdUsr":"grd_cap_id"}},{upsert:false,multi:true});

finding docs in a collection that don't match up with another collection:
  pos = db.positions.find({},{id:1}).map(function(col){return col._id;});
  db.positionTests.find({pot_pos_id:{$nin:pos}});

aggregating counts/totals based on a selected field (GROUP BY)
 -- where alerts collection includes alt_slot ['M','A','E'], and alt_run_cnt [numeric run count]
 db.alerts.aggregate([{$group:{_id:"$alt_slot",count:{$sum:1},tot_run_cnt:{$sum:"$alt_run_cnt"}}}])

Renaming a collection:
  db.userMap.renameCollection("userCMap");
  
Export records from a mongo instance:
  mongoexport --port [nnnnn] --db pfm --collection users --out /this/users.dat

Import records into a mongo instance:
  mongoimport --port [nnnnn] --host myhost --db pfm --collection users < /this/users.dat