mongo cheatsheet

//get free account here: https://mongolab.com/plans/
//free plan includes 0.5GB of storage

//refer to http://docs.mongodb.org/manual/applications/crud/

//To list all collections you currently have
db.getCollectionNames();

//To drop a collection
db.testdemo.drop();

//To create a collection. If it doesn't exist yet, it will create it for you automatically.
db.testdemo.save({fn: "Mickey", ln: "Mouse"});
db.testdemo.save({fn: "White", ln: "Snow"});

//To list all records in a collection
db.testdemo.find();

//mongodb does not give error if you attempt to query a collection that does not exist
db.nosuchcollection.find();

//To list top 5 records, sorted by last name desc. To sort in ascending, just change -1 to 1
db.testdemo.find().sort({ln:-1}).limit(5);

//to add a column to an existing record. If no matching record found, it will do nothing, no error either.
db.testdemo.update({ln: "Mouse"}, { $set: { twitter: "mickeymouse"}});

//to update an existing value in an existing record
db.testdemo.update({ln: "Mouse"}, { $set: { twitter: "@mickeymouse", followers: 100}});

//if you set upsert option = true, it will insert if no matching record is found
db.testdemo.update({ln: "Duck"}, { $set: { fn: "Donald"}}, true);

//to find records matching certain value
db.testdemo.find({ln: "Duck"});

//to remove a record based on ObjectId
db.testdemo.remove({"_id":ObjectId("533b52f0acdbe06c2cae720c")})

//to remove a record that matches the following criteria
db.testdemo.remove({ln: "Duck"});
db.testdemo.find(); //verify that record is gone

//to increment a numeric value by 1
db.testdemo.update({ln: "Mouse"}, {$inc: {followers:1}});
db.testdemo.find({ln: "Mouse"}); //verify it got incremented by 1