Is not equal MongoDB?

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Is not equal MongoDB?

$ne selects the documents where the value of the field is not equal to the specified value . This includes documents that do not contain the field . As a result, in many cases, a $ne query with an index may perform no better than a $ne query that must scan all documents in a collection.

Is not operator MongoDB?

MongoDB provides different types of logical query operators and $not operator is one of them. This operator is used to perform logical NOT operation on the specified operator expressions and select or retrieve only those documents that do not match the given operator expression.

What is explain () in MongoDB?

The $explain operator provides information on the query plan. It returns a document that describes the process and indexes used to return the query. This may provide useful insight when attempting to optimize a query. For details on the output, see cursor.

What is $or in MongoDB?

MongoDB provides different types of logical query operators and $or operator is one of them. This operator is used to perform logical OR operation on the array of two or more expressions and select or retrieve only those documents that match at least one of the given expression in the array.

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What is a mongoose?

What is a mongoose? A mongoose is any of nearly three dozen species of small bold predatory carnivores found mainly in Africa but also in southern Asia and southern Europe. Mongooses are noted for their audacious attacks on highly venomous snakes, such as king cobras.

How do I search in MongoDB?

To find documents that match a set of selection criteria, call find() with the parameter. MongoDB provides various query operators to specify the criteria. For a list of the query operators, see Query Selectors.

How do I sort in MongoDB?

Set the Sort Order

  1. In the Query Bar, click Options.
  2. Enter the sort document into the Sort field. To specify ascending order for a field, set the field to 1 in the sort document. To specify descending order for a field, set the field and -1 in the sort documents.
  3. Click Find to run the query and view the updated results.

What is exec () in MongoDB?

Apr 8 ’17 at 10:20. I don’t know about mongodb but in most other database libraries something like .exec() allows you to dynamically create queries. For example something like: var query = Product(select); if (something) {query.where(condition)}; query.exec(callback) – slebetman.

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What is Ixscan and Collscan in MongoDB?

If the query planner selects a collection scan, the explain result includes a COLLSCAN stage. If the query planner selects an index, the explain result includes a IXSCAN stage. The stage includes information such as the index key pattern, direction of traversal, and index bounds.

What is an array in MongoDB?

MongoDB Array is a flexible document structure; it will make it possible to have a field with array as a value in MongoDB. We can define an array of string, integer, embedded documents, Jason and BSON data types, array in it can be defined as any form of data types.

What is ODM in mongoose?

Mongoose is an Object Data Modeling (ODM) library for MongoDB and Node. It manages relationships between data, provides schema validation, and is used to translate between objects in code and the representation of those objects in MongoDB.

What is schema in MongoDB?

A schema is a JSON object that defines the the structure and contents of your data. You can use Realm’s BSON schemas, which extend the JSON Schema standard, to define your application’s data model and validate documents whenever they’re created, changed, or deleted. Realm supports many built-in schema types.

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How do I use the MongoDB $NE operator?

Summary: in this tutorial, you’ll learn how to use the MongoDB $ne operator to query documents from a collection. The $ne is a comparison query operator that allows you to select documents where the value of a filed is not equal to a specified value. It also includes documents that don’t contain the field.

What does $NE mean in BSON?

$ne selects the documents where the value of the field is not equal to the specified value . This includes documents that do not contain the field. For comparison of different BSON type values, see the specified BSON comparison order. Consider the following example:

What is collection in MongoDB?

MongoDB is leading NoSQL database written in C++. It is high scalable and provides high performance and availability. It works on the concept of collections and documents. Collection in MongoDB is group of related documents that are bound together.

What happens if there is no indexing in MongoDB?

If there is no indexing, then the MongoDB must scan every document in the collection and retrieve only those documents that match the query. Indexes are special data structures that stores some information related to the documents such that it becomes easy for MongoDB to find the right data file.