Mongodb - Cheat Sheet (Page 2 of 4) in pdf

Mongodb - Cheat Sheet Page 2

More information can be found from the MongoDB Tutorial

MongoDB - Cheat Sheet

Version 1.0 / 27

December 2012 / Page 2 of 4

Updating Documents

Replaces the whole document

db.ships.update({name : 'USS Prometheus'}, {name : 'USS Something'})

sets / changes certain attributes

db.ships.update({name : 'USS Something'},

{$set : {operator : 'Starfleet', class : 'Prometheus'}})

of a given document

db.ships.update({name : 'USS Something'},

removes an attribute from a

{$unset : {operator : 1}})

given document

Removing Documents

db.ships.remove({name : 'USS Prometheus'})

removes the document

removes using operator

db.ships.remove({name:{$regex:’^USS\\sE’}})

Each individual document removal is atomic with respect to a concurrent reader or writer. No client will see a document half

G+ Community Page:

removed.

115421122548465808444

Working with Indexes

Creating an index

db.ships.ensureIndex({name : 1})

Dropping an index

db.ships.dropIndex({name : 1})

Creating a compound index

db.ships.ensureIndex({name : 1, operator : 1, class : 0})

Dropping a compound index

db.ships.dropIndex({name : 1, operator : 1, class : 0})

Creating a unique compound index

db.ships.ensureIndex({name : 1, operator : 1, class : 0}, {unique : true})

Indexes – Hints & Stats

Top & Stats System Commands

Explains index usage

Shows time spent per operations per collection

db.ships.find ({'name':'USS Defiant'}).explain()

./mongotop

Index statistics

Shows snapshot on the MongoDB system

db.ships.stats()

./mongostat

Index size

db.ships.totalIndexSize()

Mongodb - Cheat Sheet Page 2

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