ZERO TO SIXTY WITH ZERO TO SIXTY WITH MONGODB AND PHP MONGODB AND PHP Jeremy Mikola jmikola

STARTING OFF STARTING OFF What sets MongoDB apart? What are documents? How do we get up and running? What's in a driver? How do we read/write documents? What else can we do?

TERMINOLOGY TERMINOLOGY { "mongodb" : "relational db", "database" : "database", "collection" : "table", "document" : "row", "index" : "index", "_id" : "primary key", "sharding" : { "shard" : "partition", "shard key" : "partition key" } }

RDBMS: THE GOOD PARTS RDBMS: THE GOOD PARTS Tried and true SQL is a rich query language ACID compliance Transactions

RDBMS: THE BAD PARTS RDBMS: THE BAD PARTS Modeling complex or polymorphic data Schema migrations Administration Scalability trade-off

MONGODB: THE GOOD PARTS MONGODB: THE GOOD PARTS Document model Flexible schemas Scalability and performance Features (aggregation, geo, GridFS)

MONGODB: THE BAD PARTS MONGODB: THE BAD PARTS Limited atomicity Consistency trade-off Query language limitations

DATABASE LANDSCAPE DATABASE LANDSCAPE Memcached Key/Value RDBMS Scalability and Performance Depth of Functionality

WHY MONGODB? WHY MONGODB? MongoDB has the best features of key/value stores, document databases and relational databases in one — John Nunemaker

RELATIONAL MODELING RELATIONAL MODELING Articles One author Many comments Many tags Authors Many articles Many comments Tags Many articles Comments One article One author

RELATIONAL MODELING RELATIONAL MODELING articles id author_id title body 1 2 Praesent ante dui Lorem ipsum… articles_to_tags id article_id tag_id 36 1 7 37 1 8 authors id name email 2 Bob [email protected] 3 John [email protected] comments id article_id author_id body 4 1 3 Morbi libero erat… 5 1 2 Dapibus quis… 6 1 3 Fusce fermentum… tags id name 7 luctus 8 rhoncus

THINGS MAY GET THINGS MAY GET OUT OF HAND OUT OF HAND

DOCUMENT MODELING DOCUMENT MODELING Articles One author Many comments One author Many tags

DOCUMENT MODELING DOCUMENT MODELING { _id: 1, title: "Praesent ante dui", body: "Lorem ipsum…", author: { name: "Bob", email: "[email protected]" }, comments: [ { body: "Morbi libero erat…", author: { name: "John", email: "[email protected]" } }, { body: "Dapibus quis…", author: { name: "Tom", email: "[email protected]" } }, ], tags: [ "luctus", "rhoncus" ] }

DOCUMENTS ARE BSON DOCUMENTS ARE BSON Zero or more key/value pairs Values are scalars, arrays, and objects Special types (e.g. binary strings, dates) Binary JSON

DOCUMENTS IN PHP DOCUMENTS IN PHP // Arrays are most common $a = ['hello' => 'world']; $b = ['things' => ['foo', 5.05, 2012]]; // Objects work, too! $a = new stdClass; $a->hello = 'world'; $b = new stdClass; $b->things = ['foo', 5.05, 2012];

GETTING UP AND GETTING UP AND RUNNING WITH MONGO RUNNING WITH MONGO IN 60 SECONDS IN 60 SECONDS * EXCLUDING DOWNLOAD TIME :) * EXCLUDING DOWNLOAD TIME :)

MONGODB.COM/DOWNLOAD-CENTER MONGODB.COM/DOWNLOAD-CENTER Compiled binaries OS X, Linux, Windows Packages MacPorts, Homebrew, Debian, CentOS Drivers for over a dozen languages

INSTALLING INSTALLING $ tar xvzf mongodb-linux-x86_64-ubuntu1604-3.4.6.tgz mongodb-linux-x86_64-ubuntu1604-3.4.6/README mongodb-linux-x86_64-ubuntu1604-3.4.6/THIRD-PARTY-NOTICES mongodb-linux-x86_64-ubuntu1604-3.4.6/MPL-2 mongodb-linux-x86_64-ubuntu1604-3.4.6/GNU-AGPL-3.0 mongodb-linux-x86_64-ubuntu1604-3.4.6/bin/mongodump mongodb-linux-x86_64-ubuntu1604-3.4.6/bin/mongorestore mongodb-linux-x86_64-ubuntu1604-3.4.6/bin/mongoexport mongodb-linux-x86_64-ubuntu1604-3.4.6/bin/mongoimport mongodb-linux-x86_64-ubuntu1604-3.4.6/bin/mongostat mongodb-linux-x86_64-ubuntu1604-3.4.6/bin/mongotop mongodb-linux-x86_64-ubuntu1604-3.4.6/bin/bsondump mongodb-linux-x86_64-ubuntu1604-3.4.6/bin/mongofiles mongodb-linux-x86_64-ubuntu1604-3.4.6/bin/mongooplog mongodb-linux-x86_64-ubuntu1604-3.4.6/bin/mongoreplay mongodb-linux-x86_64-ubuntu1604-3.4.6/bin/mongoperf mongodb-linux-x86_64-ubuntu1604-3.4.6/bin/mongod mongodb-linux-x86 64-ubuntu1604-3 4 6/bin/mongos

STARTING STARTING $ mkdir /data/db $ ./mongod [initandlisten] MongoDB starting : pid=20357 port=27017 dbpath=/data/db 64-bit [initandlisten] db version v3.4.6 [initandlisten] git version: c55eb86ef46ee7aede3b1e2a5d184a7df4bfb5b5 [initandlisten] OpenSSL version: OpenSSL 1.0.2g 1 Mar 2016 [initandlisten] allocator: tcmalloc [initandlisten] modules: none [initandlisten] build environment: [initandlisten] distmod: ubuntu1604 [initandlisten] distarch: x86_64 [initandlisten] target_arch: x86_64 [initandlisten] options: { storage: { dbPath: "/data/db" } } [initandlisten] wiredtiger_open config: create,cache_size=7453M,session_max=20 [initandlisten] Initializing full-time diagnostic data capture with directory [thread1] waiting for connections on port 27017

CONNECTING CONNECTING $ ./mongo MongoDB shell version: 3.4.6 connecting to: test > show dbs local (empty) > db.foo.insert({x: 1}) > db.foo.find() { "_id" : ObjectId("57f7aefab586b9ceed2df190"), "x" : 1 }

MONGODB ATLAS MONGODB ATLAS Hosted MongoDB as a Service Single-click deployments, upgrades, etc. Configurable scalability and redundancy Integration with MongoDB's backup service Secure (authentication, encryption, IP whitelists) Free tier available More info at mongodb.com/cloud

PHP AND HHVM DRIVERS PHP AND HHVM DRIVERS extension (ext-mongodb) Client, server, and cursor classes BSON types and encode/decode functions (mongodb/mongodb) Client, database, and collection classes Higher-level abstractions (e.g. GridFS) Installing the and PHP PHP library extension library

LET'S GET COOKING LET'S GET COOKING

CORE CLASSES CORE CLASSES MongoDB\Client MongoDB\Database MongoDB\Collection MongoDB\Driver\Cursor

CONNECTING CONNECTING // 127.0.0.1:27017 $client = new MongoDB\Client; // example.com:27018 $client = new MongoDB\Client('mongodb://example.com:27018'); // authentication $client = new MongoDB\Client('mongodb://user:password@localhost'); // replica set $client = new MongoDB\Client( 'mongodb://rs1.example.com,rs2.example.com', ['replicaSet' => 'myReplSet'] );

THE MONGODB\CLIENT CLASS THE MONGODB\CLIENT CLASS $client = new MongoDB\Client; // Select the "test" database $db = $client->test; $db = $client->selectDatabase('test'); // Select the "test.users" collection $collection = $client->test->users; $collection = $client->selectCollection('test', 'users'); // List databases on the server foreach ($client->listDatabases() as $databaseInfo) { echo $databaseInfo->getName(), "\n"; }

THE MONGODB\DATABASE CLASS THE MONGODB\DATABASE CLASS $db = $client->test; // Select the "test.users" collection $collection = $db->users; $collection = $db->selectCollection('users'); // Execute a command on the "test" database $cursor = $db->command(['serverStatus' => 1]); $serverStatus = $cursor->toArray()[0]; // List collections in the "test" database foreach ($db->listCollections() as $collectionInfo) { echo $collectionInfo->getName(), "\n"; }

THE MONGODB\COLLECTION CLASS THE MONGODB\COLLECTION CLASS $collection = $db->users; // Insert a user document for Bob $collection->insertOne(['username' => 'bob', 'roles' => ['admin']]); // Retrieve Bob's user document $user = $collection->findOne(['username' => 'bob']); // Find all admins (returns an iterable MongoDB\Driver\Cursor) $cursor = $collection->find(['roles' => 'admin']); $admins = $cursor->toArray();

THE MONGODB\COLLECTION CLASS THE MONGODB\COLLECTION CLASS $collection->count(); // Count all users $collection->count(['roles' => 'admin']); // Count only admins $collection->deleteOne(['username' => 'john']); // Delete a user $collection->deleteMany([]); // Delete all users

IDENTIFIERS AND TYPES IDENTIFIERS AND TYPES

IDENTIFIERS IDENTIFIERS // Create a user document for Tom $result = $collection->insertOne(['username' => 'tom']); var_dump($result->getInsertedCount()); var_dump($result->getInsertedId()); int(1) object(MongoDB\BSON\ObjectID)#11 (1) { ["oid"]=> string(24) "57f7d220da14d803b94fba92" }

THE THE _id _id FIELD FIELD Its value is immutable Unique to the collection ObjectID, scalar or object Indexed by default

WHAT'S IN AN OBJECTID? WHAT'S IN AN OBJECTID? 57f7d220 da14d8 03b9 4fba92 Timestamp Hostname PID Sequence 12-byte, binary string Safely generated in distributed environments Timestamp prefix useful for sorting

BSON TYPE CLASSES BSON TYPE CLASSES MongoDB\BSON\Binary MongoDB\BSON\Javascript MongoDB\BSON\ObjectID MongoDB\BSON\Regex MongoDB\BSON\Timestamp MongoDB\BSON\UTCDateTime MongoDB\Model\BSONArray MongoDB\Model\BSONDocument

WRITING WRITING

WRITING TO MONGODB WRITING TO MONGODB Inserts, updates, and upserts Consistency/performance options Avoid shooting yourself in the foot

WRITE CONCERN WRITE CONCERN {w: 0} Fire and forget Trade consistency for performance {w: 1} Ensure primary acknowledges write {w: #} or {w: "majority"} Wait for multiple acknowledgements

ACKNOWLEDGED WRITES ACKNOWLEDGED WRITES $collection = (new MongoDB\Client)->test->users; $user = $collection->findOne(['username' => 'tom']); // MongoDB\Client's default behavior $result = $collection->insertOne( $user, ['writeConcern' => new MongoDB\Driver\WriteConcern(1)] ); var_dump($result->getInsertedCount()); Uncaught MongoDB\Driver\Exception\BulkWriteException: E11000 duplicate key error collection: test.users index: _id_ dup key: { : ObjectId('57f7d220da14d803b94fba92') }

ACKNOWLEDGED WRITES ACKNOWLEDGED WRITES // Connect to a replica set URI $collection = (new MongoDB\Client('...'))->test->users; $result = $collection->insertOne( ['username' => 'tom'], ['writeConcern' => new MongoDB\Driver\WriteConcern(2)] ); var_dump($result->getInsertedCount()); // int(1)

UNACKNOWLEDGED WRITES UNACKNOWLEDGED WRITES $collection = (new MongoDB\Client)->test->users; $user = $collection->findOne(['username' => 'tom']); $result = $collection->insertOne( $user, ['writeConcern' => new MongoDB\Driver\WriteConcern(0)] ); var_dump($result->isAcknowledged()); bool(false)

UPDATING A DOCUMENT UPDATING A DOCUMENT // Change Tom's email address $result = $collection->updateOne( ['username' => 'tom'], ['$set' => ['email' => '[email protected]']] ); var_dump($result->getMatchedCount()); // int(1) var_dump($result->getModifiedCount()); // int(1) Criteria New object Overwrite entire document Apply atomic operations

UPDATING MULTIPLE DOCUMENTS UPDATING MULTIPLE DOCUMENTS // Make everyone an admin (probably a bad idea :) $result = $collection->updateMany( [], ['$addToSet' => ['roles' => 'admin']] ); var_dump($result->getMatchedCount()); // int(9) var_dump($result->getModifiedCount()); // int(9)

UPSERTING UPSERTING // If Sam doesn't exist, insert: { username: "Sam", role: "staff" } $result = $collection->updateOne( ['username' => 'sam'], ['$set' => ['role' => 'staff']], ['upsert' => true] ); var_dump($result->getMatchedCount()); // int(0) var_dump($result->getModifiedCount()); // int(0) var_dump($result->getUpsertedCount()); // int(1) var_dump($result->getUpsertedId()); // object(MongoDB\BSON\ObjectID) No multi-document operation Does the criteria match a document? Yes, update the document No, apply modifiers to criteria and insert

UPDATE OPERATORS UPDATE OPERATORS Mixed Arrays , , Numbers $currentDate $rename $set $unset $addToSet $pop $pull $pullAll $push $pushAll $bit $inc $mul

POSITIONAL UPDATES POSITIONAL UPDATES $collection = (new MongoDB\Client)->test->articles; // An article with votable comments $collection->insertOne([ '_id' => 1, 'title' => 'Praesent ante dui', 'comments' => [ ['id' => 1, 'votes' => 2, 'text' => 'Dapibus quis…'], ['id' => 2, 'votes' => 0, 'text' => 'Fusce fermentum…'], ], ]); // Upvote the second comment $collection->updateOne( ['_id' => 1, 'comments.id' => 2], ['$inc' => ['comments.$.votes' => 1]] );

QUERIES QUERIES

BASIC QUERYING BASIC QUERYING $collection->findOne(); // Retrieve one document as an array $collection->find(); // Find all documents via MongoDB\Driver\Cursor // Query on field values $collection->findOne(['lastName' => 'Smith']); $collection->find(['roles' => 'admin']); Query criteria is BSON No grammar to parse

QUERIES RETURN CURSORS QUERIES RETURN CURSORS Cursors navigate a query result Can be iterated forward and only once Convert to an array for random access Commands return cursors, too

THE MONGODB\DRIVER\CURSOR CLASS THE MONGODB\DRIVER\CURSOR CLASS $cursor = $collection->find( ['roles' => 'admin'], // Find all admins [ 'sort' => ['username' => -1], // Desc sort by username 'limit' => 10, // Limit to 10 results 'skip' => 5, // Skip the first 5 ] ); // Iterate through results foreach ($cursor as $document) { } // Get them all at once (equivalent to iterator_to_array()) $results = $cursor->toArray();

AD-HOC QUERYING AD-HOC QUERYING ARBITRARY BUSINESS REQUIREMENT #42789! ARBITRARY BUSINESS REQUIREMENT #42789! We need the usernames for all admins that use Gmail and whose accounts were created within the last year.

DATA TO QUERY DATA TO QUERY $collection = (new MongoDB\Client)->test->users; $collection->insertOne([ 'username' => 'bob', 'email' => '[email protected]', 'profile' => [ 'bio' => 'I am a data fixture.', 'createdAt' => new MongoDB\BSON\UTCDateTime, ], 'roles' => ['moderator', 'admin'], ]); // Among others…

COMPLEX CRITERIA COMPLEX CRITERIA Regular expressions Matching values in embedded objects Comparison operators Matching a value in an array

COMPLEX CRITERIA COMPLEX CRITERIA $lastYear = new DateTime('last year'); // Arbitrary Business Requirement #42789! $cursor = $collection->find( [ 'email' => new MongoDB\BSON\Regex('gmail\.com$', 'i'), 'profile.createdAt' => [ '$gt' => new MongoDB\BSON\UTCDateTime($lastYear), ], 'roles' => 'admin', ] );

FIELD PROJECTION FIELD PROJECTION // Limit returned fields to the username $cursor = $collection->find( [ 'email' => new MongoDB\BSON\Regex('gmail\.com$', 'i'), 'profile.createdAt' => [ '$gt' => new MongoDB\BSON\UTCDateTime($lastYear), ], 'roles' => 'admin', ], [ 'projection' => ['username' => 1], ] ); Retrieving a subset of fields Retrieving a slice of an array

QUERY OPERATORS QUERY OPERATORS Comparison , , Logical , Arrays , Misc Geo $gt $gte $lt $lte $ne $and $or $nor $not $all $in $nin $size $elemMatch $exists $mod $text $type $where $geoWithin $geoIntersects $near $nearSphere

AN ATOMIC PICKLE AN ATOMIC PICKLE We can query for things We can update documents atomically Can we atomically query and update?

DATA TO PROCESS DATA TO PROCESS $collection = (new MongoDB\Client)->test->jobs; $collection->insertOne([ 'task' => '…', 'inprogress' => 'false', 'priority' => 1 ]); $collection->insertOne([ 'task' => '…', 'inprogress' => 'false', 'priority' => 4 ]);

A DOCUMENT A DOCUMENT FIND AND MODIFY FIND AND MODIFY use MongoDB\Operation\FindOneAndUpdate; $collection->findOneAndUpdate( ['inprogress' => false], ['$set' => [ 'inprogress' => true, 'startedAt' => new MongoDB\BSON\UTCDateTime, ]], [ 'returnDocument' => FindOneAndUpdate::RETURN_DOCUMENT_AFTER, 'sort' => ['priority' => -1], ] ); Atomically select and modify one document Update, upsert, replace, or delete the document Return document in pre- or post-modified state

INDEXING INDEXING

INDEXES IN MONGODB INDEXES IN MONGODB B-trees Multiple indexes per collection Any field(s), top-level or embedded , , , , and Multi-key indexes for array values Sparse unique geospatial text TTL

MANAGING INDEXES MANAGING INDEXES $collection = (new MongoDB\Client)->test->things; // Ensure unique values for x (just like the _id index) $collection->createIndex(['x' => 1], ['unique' => true]); // Delegate index creation as a background task $collection->createIndex(['x' => 1], ['background' => true]); // List all indexes in the "test.things" collection foreach ($collection->listIndexes() as $indexInfo) { echo $indexInfo->getName(), "\n"; } $collection->dropIndex('x_1'); // Delete an index by name $collection->dropIndexes(); // Delete all indexes for the collection

COMPOUND INDEXES COMPOUND INDEXES $collection->createIndex(['x' => 1, 'y' => 1, 'z' => -1]); // These queries will use the index $collection->find(['x' => 'foo']); $collection->find(['x' => 'foo', 'y' => ['$gt' => 5]]); $collection->find( ['x' => 'foo', 'y' => 4], ['sort' => ['z' => -1]] ); $collection->find(['x' => "foo", 'y' => 8, 'z' => 'baz']); // This query will not by default $collection->find(['y' => 6]); Index multiple fields Direction per field (range queries, sorting) Usable for constituent field queries

PERFORMANCE TIPS PERFORMANCE TIPS Avoid non-indexed queries and table scans Keep your indexes and working set in RAM Mind your read/write ratio Support multiple queries per index Create indexes that ensure selectivity Indexing advice and FAQ

DATABASE COMMANDS DATABASE COMMANDS

DATABASE COMMANDS DATABASE COMMANDS Sharding Replication Aggregation Collections Indexing Geospatial Diagnostic Administration Shell and driver helpers for some for the rest MongoDB\Database::command() Reference list

AGGREGATION AGGREGATION

AGGREGATION AGGREGATION Aggregation framework Single-purpose aggregation commands MapReduce Hadoop adapter

REPORTING REPORTING ARBITRARY BUSINESS REQUIREMENT #27533! ARBITRARY BUSINESS REQUIREMENT #27533! We need a report listing all authors that have written an article for each tag category.

DATA TO AGGREGATE DATA TO AGGREGATE $collection = (new MongoDB\Client)->test->articles; $collection->insertOne(['author' => 'jen', 'tags' => ['politics', 'tech']]); $collection->insertOne(['author' => 'sue', 'tags' => ['business']]); $collection->insertOne(['author' => 'tom', 'tags' => ['sports']]); $collection->insertOne([ 'author' => 'bob', 'tags' => ['business', 'sports', 'tech'] ]);

MAP MAPREDUCE REDUCE $map = ' function() { for (var i = 0; i < this.tags.length; i++) { emit(this.tags[i], { authors: [this.author] }); } }';

REDUCE REDUCE MAP MAP $reduce = ' function(key, values) { var result = { authors: [] }; values.forEach(function(value) { value.authors.forEach(function(author) { if (-1 == result.authors.indexOf(author)) { result.authors.push(author); } }); }); return result; }';

MAPREDUCE MAPREDUCE $db = (new MongoDB\Client)->test; $cursor = $db->command([ 'mapreduce' => 'articles', 'map' => new MongoDB\BSON\Javascript($map), 'reduce' => new MongoDB\BSON\Javascript($reduce), 'out' => ['inline' => true], ]); foreach ($cursor->toArray()[0]['results'] as $r) { $authors = implode(', ', $r['value']['authors']); printf("%s: %s\n", $r['_id'], $authors); } business: sue, bob politics: jen sports: tom, bob tech: jen, bob

AGGREGATION FRAMEWORK AGGREGATION FRAMEWORK $collection = (new MongoDB\Client)->test->articles; $cursor = $collection->aggregate([ ['$unwind' => '$tags'], ['$group' => [ '_id' => '$tags', 'authors' => ['$addToSet' => '$author'], ]], ]); foreach ($cursor as $r) { $authors = implode(', ', $r['authors']); printf("%s: %s\n", $r['_id'], $authors); } business: bob, sue tech: bob, jen sports: bob, tom politics: jen

GRIDFS GRIDFS

GRIDFS GRIDFS File storage within MongoDB BSON collections fs.files: metadata document fs.chunks: binary data (1+ per file) MongoDB\GridFS\Bucket and PHP Streams

THE MONGODB\GRIDFS\BUCKET CLASS THE MONGODB\GRIDFS\BUCKET CLASS $db = (new MongoDB\Client)->test; // Default prefix (fs.files and fs.chunks) $bucket = $db->selectGridFSBucket(); // Custom prefix (images.files and images.chunks) $bucket = $db->selectGridFSBucket(['bucketName' => 'images']);

STORING FILES STORING FILES // Upload a file and return its _id $source = fopen('/path/to/file', 'rb'); $id = $bucket->uploadFromStream('filename', $source); // Upload bytes to a file and return its _id $stream = $bucket->openUploadStream('filename'); $id = $bucket->getFileIdForStream($stream); fwrite($stream, 'foobar'); fclose($stream);

RETRIEVING FILES RETRIEVING FILES // Download a file by its _id $id = new MongoDB\BSON\ObjectID('57f81b38da14d802e97b1b72'); $destination = fopen('/path/to/file', 'w+b'); $bucket->downloadToStream($id, $destination); // Open a readable stream for a file by its _id $stream = $bucket->openDownloadStream($id); $contents = stream_get_contents($stream);

RETRIEVING FILES BY FILENAME RETRIEVING FILES BY FILENAME // Download a file by its filename $destination = fopen('/path/to/file', 'w+b'); $bucket->downloadToStreamByName('filename', $destination); // Open a readable stream for a file by its filename $stream = $bucket->openDownloadStreamByName('filename'); $contents = stream_get_contents($stream); filename is not necessarily unique Same filename and different uploadDate → revision Filename queries select the most recent revision by default

RETRIEVING FILES BY REVISION RETRIEVING FILES BY REVISION // Open the most recent revision (default behavior) $bucket->openDownloadStreamByName('filename', ['revision' => -1]); // Open the second most recent revision $bucket->openDownloadStreamByName('filename', ['revision' => -2]); // Open the original revision (i.e. 0th) $bucket->openDownloadStreamByName('filename', ['revision' => 0]); // Open the first revision $bucket->openDownloadStreamByName('filename', ['revision' => 1]); Same options for downloadToStreamByName()

SELECTING A FILE DOCUMENT SELECTING A FILE DOCUMENT $id = new MongoDB\BSON\ObjectID('57f81b38da14d802e97b1b72'); $stream = $bucket->openDownloadStream($id); var_dump($bucket->getFileDocumentForStream($stream)); object(stdClass)#16 (6) { ["_id"]=> object(MongoDB\BSON\ObjectID)#18 (1) { ["oid"]=> string(24) "57f8228eda14d81806017242" } ["chunkSize"]=> int(261120) ["filename"]=> string(8) "filename" ["uploadDate"]=> object(MongoDB\BSON\UTCDateTime)#21 (1) { ["milliseconds"]=> string(13) "1475879566662" } ["length"]=> int(9) ["md5"]=>

DELETING FILES DELETING FILES // Delete a file (and related chunks) by its _id $id = new MongoDB\BSON\ObjectID('57f81b38da14d802e97b1b72'); $bucket->delete($id); // Drop the files and chunks collections $bucket->drop(); No API for modifying files in-place Delete and re-upload, or create a new revision

THANKS! THANKS! and (free online education) (DBaaS) Server downloads documentation PHP and HHVM extension documentation PHP library documentation MongoDB University MongoDB Atlas QUESTIONS? QUESTIONS?

PHOTO CREDITS PHOTO CREDITS http://www.flickr.com/photos/paranoidfs/7312644738/ http://www.flickr.com/photos/pagedooley/7330663394/ http://www.slxdeveloper.com/page.aspx?action=viewarticle&articleid=92 http://www.sxc.hu/photo/487816 http://www.flickr.com/photos/sharynmorrow/2224102244/ http://www.flickr.com/photos/guangye/3234191654/ http://www.flickr.com/photos/spacebarpark/6712082295/ http://www.flickr.com/photos/dierken/7998425310/ http://www.flickr.com/photos/69125796@N00/7415476606/ http://www.sxc.hu/photo/443042 http://www.flickr.com/photos/mikebaird/3898801499/ http://history.nasa.gov/ap08fj/photos/a/as08-16-2593hr.jpg