Tutorial by Examples: p

The --url flag can be tricky to use. There is a 60 second window to authenticate, and then the username/password randomly resets. So be sure to have robomongo open and ready to configure a new connection when you run the command. # get the MONGO_URL string for your app meteor mongo --url $METEOR...

This command will create a /dump directory, and store each collection in a separate BSON blob file. This is the best way to backup or transfer databases between systems. mongodump --db meteor

The analog to the meteordump command is meteorrestore. You can do a partial import by selecting the specific collection to import. Particularly useful after running a drop command. # make sure your app is running meteor # then import your data mongorestore --port 3001 --db meteor /path/to/dump...

Run meteor, open another terminal window, and run the following command. mongoexport --db meteor --collection foo --port 3001 --out foo.json

Importing into a default Meteor instance is fairly easy. Note that you can add a --jsonArray option if your json file is exported as an array from another system. mongoimport --db meteor --port 3001 --collection foo --file foo.json

Mongo supports database-to-database copying, which is useful if you have large databases on a staging database that you want to copy into a local development instance. // run mongod so we can create a staging database // note that this is a separate instance from the meteor mongo and minimongo ins...

Preallocation. Mongo sets aside disk-space in empty containers, so when the time comes to write something to disk, it doesn't have to shuffle bits out of the way first. It does so by a doubling algorithm, always doubling the amount of disk space preallocated until it reaches 2GB; and then each preal...

Delete the local database files. Just exit the Mongo shell, navigate to the /dbpath (wherever you set it up), and delete the files within that directory.

With the power of regex comes great responsibility.... db.posts.find({'text': /.*foo.*|.*bar.*/i})

db.posts.find().forEach(function(doc){ if(doc.commenters){ var firstCommenter = db.users.findOne({'_id': doc.commenters[0]._id }); db.clients.update({_id: doc._id}, {$set:{'firstPost': firstCommenter }}, false, true); var firstCommenter = db.users.findOne({'_id': do...

db.posts.find().forEach(function(doc){ if(!doc.foo){ db.posts.update({_id: doc._id}, {$set:{'foo':'bar'}}, false, true); } });

db.posts.find().forEach(function(doc){ if(doc.foo === 'bar'){ db.posts.remove({_id: doc._id}); } });

db.posts.find().forEach(function(doc){ if(doc.foo === 'bar'){ db.posts.update({_id: doc._id}, {$set:{'foo':'squee'}}, false, true); } });

db.posts.find().forEach(function(doc){ if(doc.oldfield){ // the false, true at the end refers to $upsert, and $multi, respectively db.accounts.update({_id: doc._id}, {$unset: {'oldfield': "" }}, false, true); } });

db.posts.find().forEach(function(doc){ if(doc._id){ db.posts.update({_id: doc._id}, {$set:{ timestamp: new Date(parseInt(doc._id.str.slice(0,8), 16) *1000) }}, false, true); } });

Purpose Use the CREATE SEQUENCE statement to create a sequence, which is a database object from which multiple users may generate unique integers. You can use sequences to automatically generate primary key values. When a sequence number is generated, the sequence is incremented, independent of th...

Backbone.js is made up of four separate components: Collections, Models, Routers, and Views. Each of these serve different purposes: Model - represents a single data object, but adds additional functionalities not provided by native JavaScript objects, such as an event system and a more conveni...

Using Dynamic Arrays in VBA can be quite clunky and time intensive over very large data sets. When storing simple data types in a dynamic array (Strings, Numbers, Booleans etc.), one can avoid the ReDim Preserve statements required of dynamic arrays in VBA by using the Split() function with some cl...

Now that the OCaml distribution is available on your favorite operating system, we can create your first program in OCaml: the Hello World! We have different ways to launch an OCaml program. The REPL (toplevel) You can execute your code interactively with the toplevel. With the OCaml toplevel, yo...

If you are just starting a new project, it's important to think about how you want to handle code signing. If you are new to code signing, check out the WWDC session that describes the fundamentals of code signing in Xcode. To properly code-sign your app, you have to have the following resources o...