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Transaction lock in MongoDB?
Transaction support isn’t available in MongoDB 4.0. To get similar results, use findOneAndUpdate().
Let us create a collection with documents −
> db.demo404.insertOne({"FirstName":"John"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e6f8c38fac4d418a0178592")
}
> db.demo404.insertOne({"FirstName":"Robert"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e6f8c3cfac4d418a0178593")
}
> db.demo404.insertOne({"FirstName":"Mike"});
{
"acknowledged" : true,
"insertedId" : ObjectId("5e6f8c40fac4d418a0178594")
}Display all documents from a collection with the help of find() method −
> db.demo404.find();
This will produce the following output −
{ "_id" : ObjectId("5e6f8c38fac4d418a0178592"), "FirstName" : "John" }
{ "_id" : ObjectId("5e6f8c3cfac4d418a0178593"), "FirstName" : "Robert" }
{ "_id" : ObjectId("5e6f8c40fac4d418a0178594"), "FirstName" : "Mike" }Following is the query to use findOneAndUpdate and set lock in MongoDB −
> result=db.demo404.findOneAndUpdate({"in_transaction": {"$exists": false}}, {"$set": {"in_transaction": true}});This will produce the following output −
{ "_id" : ObjectId("5e6f8c38fac4d418a0178592"), "FirstName" : "John" }
Updated on: 03-Apr-2020
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