1. shell
   1. db
   2. use database
   3. insert
   4. batchInsert
   5. update
   6. Upserts
      1. insert or update
   7. remove
   8. save
      1. if _id is exist it will update otherwise
   9. help
      1. db.help()
      2. db.mycoll.help()
      3. ...
   10. show
       1. show dbs
       2. show collections
       3. show users
       4. ...
   11. modifier
       1. $set
       2. $inc
          1. Incrementing
       3. decrementing
          1. Subtopic 1
   12. modifier array
       1. $push
       2. $addToSet
       3. $each
       4. $pop
       5. $pull
   13. db.getLastError()
   14. Query
       1. find
          1. example
             1. db.users.find({"username" : "joe", "age" : 27})
          2. Specifying Which Keys to Return
          3. Criteria
             1. $lt
             2. $lte
             3. $gt
             4. $gte
             5. $or
             6. db.raffle.find({"$or" : [{"ticket_no" : 725}, {"winner" : true}]})
             7. $in
             8. db.raffle.find({"ticket_no" : {"$in" : [725, 542, 390]}})
             9. $not
             10. db.users.find({"id_num" : {"$not" : {"$mod" : [5, 1]}}})
             11. $mod
             12. db.users.find({"id_num" : {"$mod" : [5, 1]}})
          4. Conditional Semantics
             1. db.users.find({"age" : {"$lt" : 30, "$gt" : 20}})
             2. db.users.find({"$and" : [{"x" : {"$lt" : 1}}, {"x" : 4}]})
          5. null
             1. list all
             2. db.c.find()
          6. array
             1. one of them
             2. $all
             3. match all
             4. $size
             5. $slice
          7. Embedded Documents
             1. Subtopic 1
          8. $where
       2. sort
       3. limit
       4. skip
       5. _addSpecial
          1. $maxscan
          2. $min
          3. $max
          4. $showDiskLoc
   15. Server-Side Scripting
       1. turn javascript off
          1. running mongod with the --noscripting option.
       2. use parameters like sql
   16. Cursors
       1. open
          1. var cursor = db.collection.find();
       2. cursor.hasNext()
       3. obj = cursor.next();
       4. forEach
   17. database command
       1. drop
2. data type
   1. null
   2. boolean
   3. number
   4. string
   5. date
   6. regular expression
   7. array
   8. embedded document
   9. object id
   10. binary data
   11. code
       1. JavaScript code:
3. Main Topic 3