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MongoDB Developer Notes

Inserting Documents

Any valid JSON document can be inserted into MongoDB. http://www.json.org/

db.blog.insert({
        "headline" : "Apple Reports Fourth Quarter Earnings",
        "slug" : "/apple-reports-fourth-quarter-earnings",
        "description" : "Apple reported fourth quarter earnings today, Wall Street reacted positively."
})

Inserting array elements within document

db.blog.insert({
        "headline" : "Apple Reports Fourth Quarter Earnings",
        "slug" : "/apple-reports-fourth-quarter-earnings",
        "description" : "Apple reported fourth quarter earnings today, Wall Street reacted positively.",
        "tags" : [ "AAPL", "Earnings", "Business" ]
})

Inserting sub documents

db.blog.insert({
        "headline" : "Apple Reports Fourth Quarter Earnings",
        "slug" : "/apple-reports-fourth-quarter-earnings",
        "description" : "Apple reported fourth quarter earnings today, Wall Street reacted positively.",
        "tags" : [ "AAPL", "Earnings", "Business" ],
        "author" : {
                "name" : "Jason Zucchetto",
                "title" : "Lead Editor"
        }
})

Using Javascript in shell to insert 1000 documents

for ( i = 0; i < 1000; i++ ) {
        db.blog.insert({
                "headline" : "Story " + i
        })
}

Basic Document Queries

Basic query by example

db.blog.find({ "slug" : "/apple-reports-fourth-quarter-earnings" })

Querying sub document fields (dot notation)

db.blog.find({ "author.name" : "Jason Zucchetto" })

Querying array elements

db.blog.find({ "tags" : "AAPL" })

Using Query Operators

db.people.insert({ "name" : "Bart", "age" : 10})
db.people.insert({ "name" : "Lisa", "age" : 8})
db.people.insert({ "name" : "Homer", "age" : 42})
db.people.insert({ "name" : "Marge", "age" : 40})
db.people.insert({ "name" : "Blinky"})

$gt (greater than)

db.people.find({ "age" : { $gt : 8 }})

$gte (greater than or equal to)

db.people.find({ "age" : { $gte : 10 }})

$lt (less than)

db.people.find({ "age" : { $lt : 10 }})

$lte (less than or equal to)

db.people.find({ "age" : { $lte : 10 }})

$ne (not equal)

db.people.find({ "age" : { $ne : 10 }})

$in (in list or values)

db.people.find({ "age" : { $in : [5, 10] }})

$nin (not in list or values)

db.people.find({ "age" : { $nin : [5, 10] }})

$mod (age mod 5 = 0)

db.people.find({ "age" : { $mod : [8, 0] }})

$regex (regular expression)

db.people.find({ "name" : { $regex : "j.*" }})

$exists (field exists in document)

db.people.find({ "age" : { $exists : true }})

$type (field type, string, integer, etc.)

http://docs.mongodb.org/manual/reference/operator/type/

db.people.find({ "age" : { $type : 2 }})

$not

db.people.find({ "age" : { $not : { $gt : 5 } }})

$or

db.people.find({ $or : [{ "name" : "Bart" }, { "name" : "Lisa" }]})

$and

db.people.find({ $and : [{ "name" : "Bart" }, { "age" : { $gt : 10 } }]})

$nor (not or)

db.people.find({ $nor : [{ "name" : "Bart" }, { "name" : "Lisa" }]})

$elemMatch

Insert some sample data

db.parents.insert({
        "name" : "Bart",
        "age" : 8,
        "hobbies" : [{
                "name" : "Skateboarding",
                "skill_level" : 5},
                {
                "name" : "Homework",
                "skill_level" : 1}
        ] })

db.parents.find({ "hobbies" : { $elemMatch : { "name" : "Skateboarding", "skill_level" : 5 } } })

$where (avoid)

db.parents.find({ $where : "this.name == 'Bart'" })

Querying Arrays

db.places.insert({
        "name" : "Moe's Tavern",
        "tags" : ["Bar", "Beer", "Springfield"]
        })
db.places.insert({
        "name" : "Quickie Mart",
        "tags" : ["Store", "Slushee", "Springfield"]
        })

$all

db.places.find({ "tags" : { $all : ["Springfield", "bar"] }})

$size

db.places.find({ "tags" : { $size : 3 }})

$slice (return N elements)

db.places.find({}, { "tags" : { $slice : 3 }})

Updating Documents

Update first document

db.people.update({ "name" : "Lisa" }, { $set : { "instrument" : "Saxophone"}})

Update all documents

db.people.update({ "name" : { $in : ["Bart", "Lisa"] } }, { $set : { "city" : "Springfield"} }, { multi : true})

Upserts (insert if document not found)

db.people.update({ "name" : { $in : ["Bart", "Lisa"] } }, { $set : { "city" : "Springfield"} }, { upsert : true})

$inc (incrementing a counter)

db.people.update({ "name" : "Lisa" }, { $set : { "friends" : 10}})

db.people.update({ "name" : "Lisa" }, { $inc : { "friends" : 1 }})

$ positional operator

db.schools.insert({
        "name" : "Springfield Elementary",
        "staff" : [
                {
                        "firstname" : "Seymour",
                        "lastname" : "Skinner",
                        "position" : "Principal"
                },
                {
                        "firstname" : "Edna",
                        "lastname" : "Quabopple",
                        "position" : "Teacher"
                }
        ]})

db.schools.update({ "staff.firstname" : "Edna"}, { $set : { "staff.$.position" : "5th grade teacher" }})

$rename (rename a field within a document)

db.people.update({ "name" : "Bart" }, { $rename : { "age" : "my_new_age" }});

Updating Arrays in Documents

Dot notation for array elements

db.places.update({ "name" : "Quickie Mart" }, { $set: { "tags.0" : "SLUSHEE" }})

$push (add value to array)

db.places.update({ "name" : "Quickie Mart" }, { $push: { tags : "Toothpaste" }})

$pushAll (add multiple values to array)

db.places.update({ "name" : "Quickie Mart" }, { $pushAll: { tags : ["Milk", "Eggs"] }})

$pull (remove value from array)

db.places.update({ "name" : "Quickie Mart" }, { $pull: { tags : "Toothpaste" }})

$pullAll (remove all values from array)

db.places.update({ "name" : "Quickie Mart" }, { $pullAll: { tags : ["Milk", "Eggs"] }})

$pop (remove element from beginning or end of array)

db.places.update({ "name" : "Quickie Mart" }, { $pop: { tags : 1 }})

db.places.update({ "name" : "Quickie Mart" }, { $pop: { tags : -1 }})

$addToSet (add only if value is not already in array)

db.places.update({ "name" : "Quickie Mart" }, { $addToSet: { tags : "Toothpaste" }})

db.places.update({ "name" : "Quickie Mart" }, { $addToSet: { tags : "Candy" }})

Removing Documents

db.places.remove({ "name" : "Moe's Tavern" })

Just remove one object

db.places.remove({ "name" : "Moe's Tavern" }, 1)

Creating an Index

Create index on single field

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

Create compound index

db.people.ensureIndex({ name : 1, age : 1})

Create unique index

db.people.ensureIndex({ instrument : 1}, {unique : true})

db.people.ensureIndex({ instrument : 1}, {unique : true, dropDups: true })

Create sparse index

db.people.ensureIndex({ city : 1}, {sparse : true, background: true})

Create background index

db.people.ensureIndex({ city : 1}, {background: true})

TTL index (delete document after a certain amount of time)

db.people.ensureIndex({ date_created : 1}, { expireAfterSeconds: 3600 })

Geospatial index

db.locations.ensureIndex( { lat_long : "2d" } )

db.locations.insert({name : "Palo Alto", lat_long : [-122.143019, 37.441883]})
db.locations.insert({name : "Cupertino", lat_long : [-122.032182, 37.322998]})
db.locations.insert({name : "San Jose", lat_long : [-121.894955, 37.339386]})
db.locations.insert({name : "San Francisco", lat_long : [-122.419415, 37.77493]})
db.locations.insert({name : "Los Angeles", lat_long : [-118.243685, 34.052234]})
db.locations.insert({name : "Washington, DC", lat_long : [-77.036366, 38.895112]})

// find closest locations
db.places.find({lat_long: {$near : [-122.143019, 37.441883] }})

// points within 6 degrees (~69 miles per degree)
db.places.find({lat_long: {$near : [-122.032182, 37.322998], $maxDistance: 6 }})

// within a radius of a point
db.places.find({"lat_long" : {"$within" : {"$center" : [[-122.032182, 37.322998], 5]}}})