In this tutorial, I will talk about the $[] all positional operator for arrays in MongoDB.
The $[] all positional operator in MongoDB lets you update or modify all the elements inside the given array field while conducting an update operation.
In this guide, I will explain with different examples to use the $[] all positional operator in MongoDB so you can understand how to implement its usage in your wonderful application.
So, let us get started!
The $[] All Positional Operator Syntax in MongoDB
Let us take a quick look at the $[] positional operator syntax in MongoDB:
{ update operator: { "array.$[]" : value } }
This positional operator can be used with update operations like updateMany(), update(), and so on. Below is the syntax when used with an update operation:
db.collection.updateMany(
{ query conditions },
{ update operator: { "array.$[]" : value } }
)
Let us get started with the examples to learn how to use the $[] all positional operator in the Mongo shell.
Using the $[] All Positional Operator with a Non-Nested Array Field
Let us see how we can update arrays that are not nested or embedded inside documents in our collection.
- Start up the Mongo local database server
- Use the database you want to work with and navigate into it:
show dbs
use droneStore
- Let us take a look at all the available documents in our collection:
> db.drones.find().pretty()
{
"_id" : ObjectId("61673f46b34f185eb7b2bf0c"),
"utility" : [
"Combat",
"Rescue",
"Construction",
"Cinematography",
"Range-finding Photography",
"Wildlife Monitoring"
],
"onSale" : false,
"name" : "Nimbari Gryphon Medeta 65",
"price" : 77500,
"weight" : "77 kilograms",
"additionalDetails" : {
"material" : "carbon fiber",
"moreUses" : [
"Delivery",
"Monitoring or Inspection",
"Recreation"
]
}
}
{
"_id" : ObjectId("61673f46b34f185eb7b2bf0d"),
"utility" : [
"Combat",
"Rescue",
"Construction",
"Cinematography",
"Range-finding Photography",
"Wildlife Monitoring"
],
"onSale" : false,
"name" : "X-Strimmer Eye",
"price" : 23500,
"weight" : "24 kilograms",
"additionalDetails" : {
"material" : "glass fiber",
"moreUses" : [
"Land Inspection",
"Water Inspection"
]
}
}
{
"_id" : ObjectId("61673f46b34f185eb7b2bf0e"),
"utility" : [
"Combat",
"Rescue",
"Construction",
"Cinematography",
"Range-finding Photography",
"Wildlife Monitoring"
],
"onSale" : false,
"name" : "Khai Balemosh Shefqa TRX",
"price" : 120500,
"weight" : "80 kilograms",
"additionalDetails" : {
"material" : "aluminum",
"moreUses" : [
"Monitoring or Inspection",
"Land Inspection"
]
}
}
{
"_id" : ObjectId("61673f46b34f185eb7b2bf0f"),
"utility" : [
"Combat",
"Rescue",
"Construction",
"Cinematography",
"Range-finding Photography",
"Wildlife Monitoring"
],
"onSale" : false,
"name" : "Sifinist Croma AX",
"price" : 99500,
"weight" : "97 kilograms",
"additionalDetails" : {
"material" : "lithium",
"moreUses" : [
"Videography",
"Water Inspection"
]
}
}
{
"_id" : ObjectId("61673f46b34f185eb7b2bf10"),
"utility" : [
"Combat",
"Rescue",
"Construction",
"Cinematography",
"Range-finding Photography",
"Wildlife Monitoring"
],
"onSale" : false,
"name" : "Drovce Finnifield FR-7",
"price" : 87600,
"weight" : "13 kilograms",
"additionalDetails" : {
"material" : "polysterene",
"moreUses" : [
"Land Inspection",
"Videography"
]
}
}
- Now, we will use the $[] all positional operator to update all elements of our given array. I will use this operator with the $set operator:
> db.drones.updateMany(
... { utility: "Wildlife Monitoring" },
... { $set: { "utility.$[]": "Precision Agriculture" } },
... { upsert: true }
... )
{ "acknowledged" : true, "matchedCount" : 5, "modifiedCount" : 5 }
- Let us check our documents:
> db.drones.find().pretty()
{
"_id" : ObjectId("61673f46b34f185eb7b2bf0c"),
"utility" : [
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture"
],
"onSale" : false,
"name" : "Nimbari Gryphon Medeta 65",
"price" : 77500,
"weight" : "77 kilograms",
"additionalDetails" : {
"material" : "carbon fiber",
"moreUses" : [
"Delivery",
"Monitoring or Inspection",
"Recreation"
]
}
}
{
"_id" : ObjectId("61673f46b34f185eb7b2bf0d"),
"utility" : [
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture"
],
"onSale" : false,
"name" : "X-Strimmer Eye",
"price" : 23500,
"weight" : "24 kilograms",
"additionalDetails" : {
"material" : "glass fiber",
"moreUses" : [
"Land Inspection",
"Water Inspection"
]
}
}
{
"_id" : ObjectId("61673f46b34f185eb7b2bf0e"),
"utility" : [
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture"
],
"onSale" : false,
"name" : "Khai Balemosh Shefqa TRX",
"price" : 120500,
"weight" : "80 kilograms",
"additionalDetails" : {
"material" : "aluminum",
"moreUses" : [
"Monitoring or Inspection",
"Land Inspection"
]
}
}
{
"_id" : ObjectId("61673f46b34f185eb7b2bf0f"),
"utility" : [
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture"
],
"onSale" : false,
"name" : "Sifinist Croma AX",
"price" : 99500,
"weight" : "97 kilograms",
"additionalDetails" : {
"material" : "lithium",
"moreUses" : [
"Videography",
"Water Inspection"
]
}
}
{
"_id" : ObjectId("61673f46b34f185eb7b2bf10"),
"utility" : [
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture"
],
"onSale" : false,
"name" : "Drovce Finnifield FR-7",
"price" : 87600,
"weight" : "13 kilograms",
"additionalDetails" : {
"material" : "polysterene",
"moreUses" : [
"Land Inspection",
"Videography"
]
}
}
Perfect all our elements in the given array field have been changed using the $[] all positional operator in MongoDB.
Using the $[] All Positional Operator with a Nested Array Field
Let us see how we can update arrays that are nested or embedded inside documents in our collection.
I will use the $set operator again and this time change the values of the moreUses field which is inside the additionalDetails field of all documents.
> db.drones.updateMany(
... { },
... { $set: { "additionalDetails.moreUses.$[]": "Weather Forecast" } },
... { multi: true }
... )
{ "acknowledged" : true, "matchedCount" : 5, "modifiedCount" : 5 }
> db.drones.find().pretty()
{
"_id" : ObjectId("61673f46b34f185eb7b2bf0c"),
"utility" : [
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture"
],
"onSale" : false,
"name" : "Nimbari Gryphon Medeta 65",
"price" : 77500,
"weight" : "77 kilograms",
"additionalDetails" : {
"material" : "carbon fiber",
"moreUses" : [
"Weather Forecast",
"Weather Forecast",
"Weather Forecast"
]
}
}
{
"_id" : ObjectId("61673f46b34f185eb7b2bf0d"),
"utility" : [
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture"
],
"onSale" : false,
"name" : "X-Strimmer Eye",
"price" : 23500,
"weight" : "24 kilograms",
"additionalDetails" : {
"material" : "glass fiber",
"moreUses" : [
"Weather Forecast",
"Weather Forecast"
]
}
}
{
"_id" : ObjectId("61673f46b34f185eb7b2bf0e"),
"utility" : [
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture"
],
"onSale" : false,
"name" : "Khai Balemosh Shefqa TRX",
"price" : 120500,
"weight" : "80 kilograms",
"additionalDetails" : {
"material" : "aluminum",
"moreUses" : [
"Weather Forecast",
"Weather Forecast"
]
}
}
{
"_id" : ObjectId("61673f46b34f185eb7b2bf0f"),
"utility" : [
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture"
],
"onSale" : false,
"name" : "Sifinist Croma AX",
"price" : 99500,
"weight" : "97 kilograms",
"additionalDetails" : {
"material" : "lithium",
"moreUses" : [
"Weather Forecast",
"Weather Forecast"
]
}
}
{
"_id" : ObjectId("61673f46b34f185eb7b2bf10"),
"utility" : [
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture",
"Precision Agriculture"
],
"onSale" : false,
"name" : "Drovce Finnifield FR-7",
"price" : 87600,
"weight" : "13 kilograms",
"additionalDetails" : {
"material" : "polysterene",
"moreUses" : [
"Weather Forecast",
"Weather Forecast"
]
}
}
Perfect! We have successfully selected and used the all positional operator to update all elements of the given array field.
Read More: $pullAll Operator in MongoDB: Easy Guide
Conclusion
In this article, we learned how to use the $[] all positional operator in MongoDB. To learn further, follow CodeForGeek.com!
Noteworthy References
https://docs.mongodb.com/manual/reference/operator/update/positional-all/
