Mongo DB

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Mongo DB#

MongoDB is a non-SQL database that stores data in JSON-like documents.

CRUD#

Consider the CURD operations in MongoDB. The following list show the collection methods (<database>.<collection>.<method>):

  • Insert data:

    • insertOne.

    • insertMany.

  • The find method to search data.

  • Delete data:

    • deleteOne.

    • deleteMany.

The following cell inserts document into the users collection:

mongosh --eval "db.users.insertOne({
    name: 'Alice',
    age: 30,
    email: 'alice@example.com'
})" > /dev/null

The find method returns the created document:

mongosh --eval "db.users.find({})"

]0;mongosh mongodb://127.0.0.1:27017/?directConnection=true&serverSelectionTimeoutMS=2000[
  {
    _id: ObjectId('68f774a651826e5330ce5f47'),
    name: 'Alice',
    age: 30,
    email: 'alice@example.com'
  }
]

The following cell uses the updateMany method to change the age attribute and displays the result.

mongosh --eval "db.users.updateMany(
    {},
    { \$set: { age: 29 } }
)" > /dev/null
mongosh --eval "db.users.find({})"

]0;mongosh mongodb://127.0.0.1:27017/?directConnection=true&serverSelectionTimeoutMS=2000[
  {
    _id: ObjectId('68f774a651826e5330ce5f47'),
    name: 'Alice',
    age: 29,
    email: 'alice@example.com'
  }
]

The following cell executes the deleteMany command with an empty condition; therefore, all documents in the corresponding collection will be deleted.

mongosh --eval "db.users.deleteMany({})" > /dev/null

The result of the find returns no documents.

mongosh --eval "db.users.find({})"

]0;mongosh mongodb://127.0.0.1:27017/?directConnection=true&serverSelectionTimeoutMS=2000
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