This post will focus on the logical
operators that are available in
momgodb.I will use Java for the
illustration purpose of these
operators. You can use any of
the language for which mongo
driver is available. For the comparison operators you can refer the previous post here.
There are 4 logical operators that have been documented in mongodb specs.
We will continue with the same example that we have seen in the previous post. Continue reading Logical Querying MongoDB Java Example→
In the previous post we have seen
different variations of find() method ,
but in real life we need much more than the exact matching e.g we want to query in ranges (using in ) , combine multiple conditions together (using OR , AND) , using negation etc. In this post we will cover the comparison query operators that comes under the conditional querying in MongoDB :
In the earlier post Mongodb java Hello World Example we have seen some basic operations on the MongoDB and searching the document was one of them there we had used find().In this post we will more focus on querying mongdb with java using find() method that is basically used for querying documents in mongodb collections. We will see that how we can use find() in different ways to meet our query needs.Below are the 4 basic scenarios that we are going to cover under querying mongodb java example.
Fetching all the documents from a collection.
Fetching a subset of documents from a collection.
Fetching only selected keys of a document from a collection.
Exclude some keys of a document from a collection.
In the previous post we have seen some of the basics on the primary keys and ObjectId in MongoDB.Now its time to get our hands dirty with some code , here I am using Java to interact with our mongo database. In this MongoDB Java Hello World example we will cover the following points : –
MongoDB has its own style of storing the documents in the collection and providing the uniqueness to these documents is an important aspect of MongoDB.
So , it is very important that before we go into the higher end of Mongo we should understand what are _id and ObjectId in MongoDB.