C#.NET – MongoDB Find Empty field in the document

Today in the article we shall learn how to use query using C#.NET – MongoDB Find Empty Field In The Document for the given collection. We shall verify queries using MongoShell or UI tools like a Compass UI.

We shall also see a C# MongoDB query to get all documents where the fields are empty in the mongo collection.

Today in this article, we will cover below aspects,

We shall also see a C# MongoDB query to get all the records fields that are not empty.

Getting started

I have a sample MongoDB document as below in one of the collections. Here we shall be trying to search all the documents where the State field is empty.

C# Mongo- Find documents when a field is Empty

The below query matches documents where State field is empty

Query Pattern

{ Field Name : { $eq : "" } }

Example Query

{ State : {$eq : "" } }

C# Mongo Query Pattern

var tempQuery = new BsonDocument
                 {
                     {"State" , new BsonDocument {

                      { "$eq", string.Empty }
                     }}
                 };

Alternatively, please use the below builder pattern to create a query,

Note:

In the above query $eq an aggregate query compares two values (support both value and type) and returns:

• true when the values are matching

• false when the values are not matching

Syntax

{ $eq: [ <expression1>, <expression2> ] }

C# Mongo- Find documents when a field is not Empty

Query Pattern

{ Field Name : { $ne: "" } }

Example Query

{ State : {$ne: "" } }

C# Mongo Query

The below query matches documents where the “State” field is empty or “”

var tempQuery = new BsonDocument
                 {
                     {"State" , new BsonDocument {

                      { "$ne", string.Empty }
                     }}
                 };

That’s all, So today we learned the simple mongo query for identifying the records where the field is null or not set. It’s pretty easy to prepare the query for such needs.

References:

• MongoDB Naming Conventions and Standards

• MongoDB Query – Fields not set or Field is null

Do you have any comments or ideas or any better suggestions to share?

Please sound off your comments below.

Happy Coding !!

---

Please bookmark this page and share it with your friends. Please Subscribe to the blog to receive notifications on freshly published(2024) best practices and guidelines for software design and development.

---