MongoDB Articles - Page 530 of 130

You can use aggregate function to update MongoDB field using the value of another field. Here, we will create two collections:namestudentInformation CollectionThe query to create first collection with documents is as follows:> db.name.insert({"FirstName":"John", "LastName":"Smith"}); WriteResult({ "nInserted" : 1 })Now you can display all documents from the collection with the help of find() method. The query is as follows:> db.name.find().pretty();The following is the output that displays the collection “name” documents:{    "_id" : ObjectId("5c6c00dd68174aae23f5ef55"),    "FirstName" : "John",    "LastName" : "Smith" } CollectionThe query to create second collection with documents is as follows:> db.studentInformation.insert({"StudentFirstName":"Carol", "StudentLastName":"Taylor"}); WriteResult({ "nInserted" : 1 })Now ... Read More

You can use projection operator $elemMatch to filter in queried element in an object array in MongoDB collection. To retrieve only the queried element in an object array in MongoDB, let us first create a collection with documents object array.The query is as follows:> db.objectArray.insert({"Persons":[    {"PersonName":"Adam", "PersonSalary":25000}, {"PersonName":"Larry", "PersonSalary":27000    }]});    WriteResult({ "nInserted" : 1 }) > db.objectArray.insert({"Persons":[    {"PersonName":"David", "PersonSalary":32000}, {"PersonName":"Carol", "PersonSalary":77000    }]});    WriteResult({ "nInserted" : 1 })Now you can display all the documents with the help of find(). The query is as follows:> db.objectArray.find().pretty();The following is the output:{    "_id" : ObjectId("5c6bfadc68174aae23f5ef53"),    "Persons" ... Read More

Open source databases are those databases who have an open source code i.e anyone may view the code, study it or even modify it. Open source databases could be relational (SQL) or non relational (NoSQL).Why use Open Source Databases?It is quite expensive to create and maintain a database for any company. A huge chunk of the total software expenditure is used to handle databases. So, it is feasible to switch to low cost open source databases. This saves companies a lot of money in the long run.Open Source Databases in useThere many different open source databases in the market. All ... Read More

We can use the PyMongo library (the official Mongodb driver for Python) to connect to a Mongodb database and use it to insert, update, delete, etc objects. To include date and time information, Mongodb supports ISODate format, and PyMongo provides direct support for Python's datetime.datetime objects. There are multiple ways to prepare a Python date object for insertion into MongoDB, which we will discuss here: Create and Insert Date Object to MongoDB Using datetime.datetime.utcnow() The simplest way to create a Python date object that can be inserted into MongoDB is by using datetime.datetime.utcnow() from the datetime module. You can use ... Read More