BSON is the binary encoding of JSON-like documents that MongoDB uses when storing documents in collections. It adds support for data types like Date and binary that aren’t supported in JSON. In practice, you don’t have to know much about BSON when working with MongoDB, you just need to use the native types of your … Read more
Short Answer Just to add a direct response to your initial question: YES, if you use BSON Object ID generation, then for most drivers the IDs are almost certainly going to be unique across collections. See below for what “almost certainly” means. Long Answer The BSON Object ID’s generated by Mongo DB drivers are highly … Read more
This is addressed by the respective FAQ Q: How does Amazon DynamoDB differ from Amazon SimpleDB? Which should I use? (hash link no longer works, but use in-page Find to locate question within page) to some extent already, with the most compact summary at the end of the paragraph: While SimpleDB has scaling limitations, it … Read more
After trying for several hours, I finally did it. Make sure: you added the <MONGODB_PATH>\bin directory to the system variable PATH run command prompt as administrator Steps: step 1: execute this command: D:\mongodb\bin>mongod –remove Step 2: execute this command after opening command prompt as administrator: D:\mongodb\bin>mongod –dbpath=D:\mongodb –logpath=D:\mongodb\log.txt –install NOTE: you can also append –serviceName … Read more
The BASE acronym was defined by Eric Brewer, who is also known for formulating the CAP theorem. The CAP theorem states that a distributed computer system cannot guarantee all of the following three properties at the same time: Consistency Availability Partition tolerance A BASE system gives up on consistency. Basically available indicates that the system … Read more
There is nothing like a silver bullet, everything is built to solve specific problems and has its own pros and cons. It is up to you, what problem statement you have and what is the best fitting solution for that problem. I will try to answer your questions one by one in the same order … Read more
It’s actually not correct that MongoDB is not ACID-compliant. On the contrary, MongoDB is ACID-compilant at the document level. Any update to a single document is Atomic: it either fully completes or it does not Consistent: no reader will see a “partially applied” update Isolated: again, no reader will see a “dirty” read Durable: (with … Read more
EDIT Sept 2022: JMESPath seems to be the most widely-used, fastest-growing, and best-reviewed of alternatives for this. It has many features, including “where”-style filters. ORIGINAL: Sure, how about: JsonPath. Json Query They all seem to be a bit work in progress, but work to some degree. They are also similar to XPath and XQuery conceptually; … Read more
It really is an “it depends” kinda question. Some general points: NoSQL is typically good for unstructured/”schemaless” data – usually, you don’t need to explicitly define your schema up front and can just include new fields without any ceremony NoSQL typically favours a denormalised schema due to no support for JOINs per the RDBMS world. … Read more
This is a great question, something I have pondered over quite a bit. I will summarize my lessons learned: You can easily use Lucene/Solr in lieu of MongoDB for pretty much all situations, but not vice versa. Grant Ingersoll’s post sums it up here. MongoDB etc. seem to serve a purpose where there is no … Read more