Mongo DB query operators:

This past few months, I have spent time learning the back-end technologies and how they are working. In this journey, I discovered Mongo DB,which is flexible and allows developers to quickly store large amounts of unstructured data.

So today we are going to learn how to write MongoDB queries such as:

CRUD Operations:

• Create: insertOne(), insertMany()
• Read: findOne(), find()
• Update: updateOne(), update()
• Delete: seleteOne(), deleteMany()

More advanced query operations using:

• Comparison query operators : $gt , $lt , $gte , $lte
• Set Operators: $in, $all, $nin

let's get started

Create operations:

Those Create or Insert operations give us the ability to add a new document to a collection. We can use:

• insertOne:inserts a single document into a collection.
• insertMany: inserts multiple documents into a collection.

Read Operations:

We use those operations to get data from our Mongo DB database. We can use these methods:

• find: This method is called on the collection youd like to query.
• findOne:This method is used to retrieve a single document from a collection.

Update Operations:

With Update operations, we can modify existing documents or documents in a collection. Lets go through the update methods:

• updateOne: This method is used to update a single document.
• updateMany:This method is used to update multiple documents.

Consider the following:

Delete Operations:

ThedeleteOne()anddeleteMany()methods are used to remove documents from a collection. Lets see how these methods work:

• deleteOne:This method is used to delete a single document in a collection.
• deleteMany:This method is used to delete multiple documents in a collection

Comparison Query Operators:

These are tools to locate the requested data in a database. So we use,$lt,$lte,$gt, and$gteset of operators to achieve this. Lets look at them individually:

• $gt: Match if the requested value is "greater than" the value provided in the query;
• $gte: Match if the requested value is "greater than or equal to" the value provided in the query;
• $lt: Match if the requested value is "less than" the value provided in the query;
• $lte: Match if the requested value is "less than or equal to" the value provided in the query;

Set Operators:

Set operators includes$in,$nin, and$all. These query operators take a list of one or more values. Lets look at them individually:

• $in:This operator will return a document if any of the given values matches the search field. If the field holds an array, the$inoperator will return all the documents in a collection where at least one of the given values matches the search field.
• $nin:$nin(not in) returns a document only when none of the given elements matches the search field.
• $all:$allmatches if all the given elements match the search key.

I learned a lot during these few months, and I hope you did learn a thing or two from reading this.

Please let me know if there's anything wrong with this article. I would love to correct and improve it.