Find in mongodb shell
By default, queries in MongoDB return all fields in matching documents. To limit the amount of data that MongoDB sends to applications, you can include a projection document to specify or restrict fields to return. This page provides examples of query operations with projection using the db. The examples on this page use the inventory collection. To populate the inventory collection, run the following:.SEE VIDEO BY TOPIC: 04 MongoDB Shell and MongoDB Server
SEE VIDEO BY TOPIC: MongoDB Essentials - Complete MongoDB Guide : How Cursor works in find()Content:
MongoDB Query Document Using Find() Method (Examples)
I have written a very simple script to print the count of some states of a worker script. However I cannot print error messages which I had queried and projected with find. Here is the script:. I couldn't find something in the MongoDB documentation about this but just a hint would really help. I'm not sure which driver this is, but in Node. You are printing the cursor object and not the results. It's probably why it prints DBQuery Learn more.
Asked 5 years, 1 month ago. Active 5 years, 1 month ago. Viewed 3k times. You probably need to use findOne method rather than find as the latter only returns a cursor not the actual documents. You are currently printing the contents of a cursor rather than the results of the query see: Printing mongodb shell output to File.
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You can retrieve previous commands issued in the mongo shell with the up and down arrow keys. The mongo shell can be started with numerous options. See mongo shell page for details on all available options. The following table displays some common options for mongo :. Start mongo shell without connecting to a database.
MongoDB Query Document using find() with Example
There are totally six methods available in Mongo DB by which we can fetch particular records. Find method consists of two parameters by which we can fetch a particular record. If we don't use these two parameters then the find method will return all the documents available within the MongoDB collection. Query — This is an optional parameter which defines the selection criteria. In simple words, what you want to search within a collection will be defined as a query. Projection — This is an optional parameter which defines what to return when the query criteria successfully meet. In simple words, it is a kind of decision making which will take the decision upon the criteria.
The examples on this page use the inventory collection. To populate the inventory collection, run the following:. Populate the inventory collection with the following documents:. The driver provides com. Filters helper methods to facilitate the creation of filter documents.
There are two ways to find an item from the MongoDB database. One is through MongoDB find method and the other is through findOne method. MongoDB find method fetches the document in a collection and returns the cursor for the documents matching the criteria requested by the user.
The method of fetching or getting data from a MongoDB database is carried out by using queries. MongoDB provides a function called db. During the course of this tutorial, you will see how this function is used in various ways to achieve the purpose of document retrieval. Basic query operations The basic query operations cover the simple operations such as getting all of the documents in a MongoDB collection. Code Explanation: Employee is the collection name in the MongoDB database The find command is an in-built function which is used to retrieve the documents in the collection.
This document provides an overview of accessing this help information. To see the list of options and help for starting the mongo shell, use the --help option from the command line:. To see the list of help, in the mongo shell, type help :. In the mongo shell:. To see the list of databases on the server, use the show dbs command: . To see the list of help for methods you can use on the db object, call the db. To see the implementation of a method in the shell, type the db.
Executes a query and returns the first batch of results and the cursor id, from which the client can construct a cursor. Rather than run the find command directly, you can use the db. Changed in version 4. Use the maxTimeMS option instead. The find command has the following syntax:.
This page documents the mongo shell method, and does not refer to the MongoDB Node. Specifies the order in which the query returns matching documents. You must apply sort to the cursor before retrieving any documents from the database. The sort method has the following parameter:.
This page provides examples of query operations on array fields using the db. The examples on this page use the inventory collection. To populate the inventory collection, run the following:.