check with either: ps -edaf | grep mongo | grep -v grep # “ps” flags may differ on your OS or /etc/init.d/mongodb status # for MongoDB version < 2.6 /etc/init.d/mongod status # for MongoDB version >= 2.6 or service mongodb status # for MongoDB version < 2.6 service mongod status # for MongoDB version >= … Read more
Relational databases enforces ACID. So, you will have schema based transaction oriented data stores. It’s proven and suitable for 99% of the real world applications. You can practically do anything with relational databases. But, there are limitations on speed and scaling when it comes to massive high availability data stores. For example, Google and Amazon … Read more
Good question, I was looking into this myself as well. Create a new version on each change I came across the Versioning module of the Mongoid driver for Ruby. I haven’t used it myself, but from what I could find, it adds a version number to each document. Older versions are embedded in the document … Read more
There is no such thing as NoSQL! NoSQL is a buzzword. For decades, when people were talking about databases, they meant relational databases. And when people were talking about relational databases, they meant those you control with Edgar F. Codd’s Structured Query Language. Storing data in some other way? Madness! Anything else is just flatfiles. … Read more
I’ll post this as an answer purely to support the conversation – Tim Mahy , nawroth , and CraigTP have suggested viable databases. CouchDB would be my preferred due to the use of Erlang, but there are others out there. I’d say ACID does not contradict or negate the concept of NoSQL… While there seems … Read more
You have two options: FLUSHDB – clears currently active database FLUSHALL – clears all the existing databases
I know this is old, but it still comes up when you search for the comparison. We were using Mongo, have moved almost entirely to Dynamo, which is our first choice now. Not because it has more features, it doesn’t. Mongo has a better query language, you can index within a structure, there’s lots of … Read more
Multi update was added recently, so is only available in the development releases (1.1.3). From the shell you do a multi update by passing true as the fourth argument to update(), where the the third argument is the upsert argument: db.test.update({foo: “bar”}, {$set: {test: “success!”}}, false, true); For versions of mongodb 2.2+ you need to … Read more
My current project actually. Storing 18,000 objects in a normalised structure: 90,000 rows across 8 different tables. Took 1 minute to retrieve and map them to our Java object model, that’s with everything correctly indexed etc. Storing them as key/value pairs using a lightweight text representation: 1 table, 18,000 rows, 3 seconds to retrieve them … Read more
Definitely Relational. Unlimited flexibility and expansion. Two corrections, both in concept and application, followed by an elevation. Correction It is not “filtering out the un-needed data”; it is selecting only the needed data. Yes, of course, if you have an Index to support the columns identified in the WHERE clause, it is very fast, and … Read more