FAQ: CRUD II: Inserting and Updating - Review

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This community-built FAQ covers the “Review” exercise from the lesson “CRUD II: Inserting and Updating”.

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This exercise can be found in the following Codecademy content:

[Beta] Learn MongoDB

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Here are my solutions to the “Optional Tasks”.

Task 1. Rename the listingsAndReviews collection to a name of your choice.

show dbs
use restaurants
show collections

Use this operation to rename the collection to “listings":

db.listingsAndReviews.renameCollection("listings")

Task 2. Update all the restaurants from your favorite NYC borough by removing the grades field. They are all a “A” in your eyes!

db.listings.updateMany({ borough: "Manhattan"}, {$unset: {"grades": ""}} )

The array fields named “grades" has now been deleted for all restaurants in Manhattan.

Tasks 3. Use .bulkWrite() to perform the following operations in any order: - Add three documents using insertOne. - Update two documents using updateMany. - Replaces a document using replaceOne.

This task was very tough for me.

Here is how I worked my way through it.

I found the syntax for the .bulkWrite() method at the MongoDB website. I use this page as a reference for the syntax:
db.collection.bulkWrite() — MongoDB Manual
https://www.mongodb.com/docs/manual/reference/method/db.collection.bulkWrite/#definition

Syntax for bulkWrite() operaton:

db.collection.bulkWrite(
  [ <operation 1>, <operation 2>, ... ]
)

So, based on the tasks in the exercise the overall structure of the bulkWrite operation looks like this:

db.collection.bulkWrite(
  [ insertOne(), insertOne(), insertOne(), updateMany(), replaceOne() ]
)

I started with creating each individual operation (insertOne, updateMany, replaceOne) and tested each of them in the Codecademy command line.

I also tested them individually with the bulkWrite() method.

Finally, I put all the operations together into one big bulkWrite() operation.

insertOne()

The MongoDB code looks like this:

{ insertOne: { address: { building: "111", coord: [ 11.11, 11.11 ], street: "1 Avenue", zipcode: "11111" }, borough: "Manhattan", cuisine: "Mexican", name: "1 Place", restaurant_id: "11111111" }
}, 
{ insertOne: { address: { building: "222", coord: [ 22.22, 22.22 ], street: "2 Avenue", zipcode: "22222" }, borough: "Manhattan", cuisine: "Mexican", name: "2 Place", restaurant_id: "22222222" }
}, 
{ insertOne: { address: { building: "333", coord: [ 33.33, 33.33 ], street: "3 Avenue", zipcode: "33333" }, borough: "Manhattan", cuisine: "Mexican", name: "3 Place", restaurant_id: "33333333" } 
}

Testing insertOne() in command line in Codecademy with 1 restaurant:

db.listings.insertOne({ address: { building: "111", coord: [ 11.11, 11.11 ], street: "1 Avenue", zipcode: "11111" }, borough: "Manhattan", cuisine: "Mexican", name: "1 Place", restaurant_id: "11111111" })

Check if it was created correctly with this command:

listings.find({ name: "1 Place" })

Testing in command line in Codecademy with bulkWrite() with 3 restaurants:

db.listings.bulkWrite( [ { insertOne: { address: { building: "111", coord: [ 11.11, 11.11 ], street: "1 Avenue", zipcode: "11111" }, borough: "Manhattan", cuisine: "Mexican", name: "1 Place", restaurant_id: "11111111" }}, { insertOne: { address: { building: "222", coord: [ 22.22, 22.22 ], street: "2 Avenue", zipcode: "22222" }, borough: "Manhattan", cuisine: "Mexican", name: "2 Place", restaurant_id: "22222222" }}, { insertOne: { address: { building: "333", coord: [ 33.33, 33.33 ], street: "3 Avenue", zipcode: "33333" }, borough: "Manhattan", cuisine: "Mexican", name: "3 Place", restaurant_id: "33333333" } } ] )

The code will create 3 new restaurants.

You can use this code to see them:

db.listings.find({ name: { "$in" : [ "1 Place", "2 Place", "3 Place" ] }})

updateMany()

db.listings.updateMany( { name: { "$in" : [ "Cafe Bar", "Wakamba" ] } }, { $set: { cuisine: “Grill“ } } );

This code will change the cuisine to “Grill" in the two restaurants named “Cafe Bar" and “Wakamba".

And with bulkWrite():
db.listings.bulkWrite( [ { updateMany : { "filter" : { name: { "$in" : [ "Dudes", "Wakamba" ] } }, "update" : { $set: { cuisine: "Thai" }} } } ] );

You can use this code to see the change:
db.listings.find({ name: { "$in" : [ "Cafe Bar", "Wakamba" ] }})

Be aware that when you use the updateMany() method with the bulkWrite method you must use the fields “filter" and “update":

db.collection.bulkWrite( [ { updateMany : { "filter" : <document>, "update" : <document or pipeline>, // Changed in MongoDB 4.2 "upsert" : <boolean>, "collation": <document>, // Available starting in 3.4 "arrayFilters": [ <filterdocument1>, ... ], // Available starting in 3.6 "hint": <document|string> // Available starting in 4.2.1 } } ] )

This was very confusing for me until I found it in the documentation:

db.collection.bulkWrite() — MongoDB Manual
https://www.mongodb.com/docs/manual/reference/method/db.collection.bulkWrite/#std-label-bulkwrite-write-operations-updateOneMany

replaceOne()

replaceOne() replace the entire document, while updateOne() allows for updating fields. Since replaceOne() replaces the entire document - fields in the old document not contained in the new one will be lost - only the new fields are added.

This code will replace the document with the restaurant name “Mozzarella" with a new document where the name is “New Mozzarella" and a new field called “taste" with the value “Juicy".

db.listings.replaceOne( { name: "Mozzarella" }, { replacement: { name: "New Mozzarella", taste: "Juicy" } } );

Now with the bulkWrite method:
db.listings.bulkWrite( [ { replaceOne: { filter: { name: "Mozzarella" }, replacement: {name: "New Mozzarella", taste: "Juicy"}}} ] );

Again, you must use the fields “filter" and “replacement" (not “update") when replaceOne() is used together with bulkWrite().

You can use this code to see the change made to the document:
db.listings.find({ name: "New Mozzarella"})

Now it is time to combine all the code to form one big bulkWrite() operation that comprises all 5 write operations in the above:

db.listings.bulkWrite( 
  [ 
   { insertOne : 
     { 
      address: { building: "111", coord: [ 11.11, 11.11 ], street: "1 Avenue", zipcode: "11111" }, borough: "Manhattan", cuisine: "Mexican", name: "1 Place", restaurant_id: "11111111" 
     }
   }, 
   { insertOne : 
     { 
      address: { building: "222", coord: [ 22.22, 22.22 ], street: "2 Avenue", zipcode: "22222" }, borough: "Manhattan", cuisine: "Mexican", name: "2 Place", restaurant_id: "22222222" 
     }
   }, 
   { insertOne : 
     { 
      address: { building: "333", coord: [ 33.33, 33.33 ], street: "3 Avenue", zipcode: "33333" }, borough: "Manhattan", cuisine: "Mexican", name: "3 Place", restaurant_id: "33333333" 
     }
   }, 
   { updateMany : 
     { 
      "filter" : { name: { "$in" : [ "Cafe Bar", "Wakamba" ] } }, 
      "update" : { $set: { cuisine: "Grill" }} 
     } 
   }, 
   { replaceOne : 
     { 
      "filter" : { name: "Mozzarella" }, 
      "replacement" : { name: "New Mozzarella", taste: "Juicy" }
     }
   } 
  ] 
)

You can copy-paste the following code block to test it in the command line in Codecademy (I never found out how to write multi-line code in the Codecademy command line).

Before you do remember to reset the exercise.
Click “Get Unstuck>Reset Exercise>Reset"
Plus, also make sure that the name of the collection is changed to “listings".

db.listings.bulkWrite( [ { insertOne: { address: { building: "111", coord: [ 11.11, 11.11 ], street: "1 Avenue", zipcode: "11111" }, borough: "Manhattan", cuisine: "Mexican", name: "1 Place", restaurant_id: "11111111" }}, { insertOne: { address: { building: "222", coord: [ 22.22, 22.22 ], street: "2 Avenue", zipcode: "22222" }, borough: "Manhattan", cuisine: "Mexican", name: "2 Place", restaurant_id: "22222222" }}, { insertOne: { address: { building: "333", coord: [ 33.33, 33.33 ], street: "3 Avenue", zipcode: "33333" }, borough: "Manhattan", cuisine: "Mexican", name: "3 Place", restaurant_id: "33333333" } }, { updateMany : { "filter" : { name: { "$in" : [ "Cafe Bar", "Wakamba" ] } }, "update" : { $set: { cuisine: "Grill" }} } }, { replaceOne: { filter: { name: "Mozzarella" }, replacement: {name: "New Mozzarella", taste: "Juicy"}}} ] )

Check that it worked with the following commands.

Command: db.listings.find({ name: "New Mozzarella"})
Output:

[
  {
    _id: ObjectId("5eb3d669b31de5d588f47d6e"),
    name: 'New Mozzarella',
    taste: 'Juicy'
  }
]

Command: db.listings.find({ name: { "$in" : [ "Cafe Bar", "Wakamba" ] }}, {grades: 0, address:0})
Output:

[
  {
    _id: ObjectId("5eb3d668b31de5d588f43081"),
    borough: 'Manhattan',
    cuisine: 'Grill',
    name: 'Wakamba',
    restaurant_id: '40564625'
  },
  {
    _id: ObjectId("5eb3d668b31de5d588f4305b"),
    borough: 'Queens',
    cuisine: 'Grill',
    name: 'Cafe Bar',
    restaurant_id: '40561796'
  }
]

Command: db.listings.find({ name: { "$in" : [ "1 Place", "2 Place", "3 Place" ] }})
Output:

[
  {
    _id: ObjectId("6465cf28ebdaa1826aa08000"),
    address: {
      building: '111',
      coord: [ 11.11, 11.11 ],
      street: '1 Avenue',
      zipcode: '11111'
    },
    borough: 'Manhattan',
    cuisine: 'Mexican',
    name: '1 Place',
    restaurant_id: '11111111'
  },
  {
    _id: ObjectId("6465cf28ebdaa1826aa08001"),
    address: {
      building: '222',
      coord: [ 22.22, 22.22 ],
      street: '2 Avenue',
      zipcode: '22222'
    },
    borough: 'Manhattan',
    cuisine: 'Mexican',
    name: '2 Place',
    restaurant_id: '22222222'
  },
  {
    _id: ObjectId("6465cf28ebdaa1826aa08002"),
    address: {
      building: '333',
      coord: [ 33.33, 33.33 ],
      street: '3 Avenue',
      zipcode: '33333'
    },
    borough: 'Manhattan',
    cuisine: 'Mexican',
    name: '3 Place',
    restaurant_id: '33333333'
  }
]
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