Update documents in collection in mongoDB

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Update documents (records) in collection (table) in mongoDB >


1) Before updating let’s create and query collection in MongoDB


Let's create collection and insert documents in it before update >
> db.employee.insert({id : 1,  firstName:"ankit"})
> db.employee.insert({id : 2,  firstName:"sam"})
First line above will create table (or collection) (if table already exists it will insert documents in it).


Let's query/see what is there in collection before update >
> db.employee.find();
{ "_id" : ObjectId("584ebed11127dea5ece72742"), "id" : 1, "firstName" : "ankit" }
{ "_id" : ObjectId("584ebee21127dea5ece72743"), "id" : 2, "firstName" : "sam" }




2) UPDATE Example1 in MongoDB >
Let’s UPDATE firstname where id=1 >
We will use update method of mongoDB
> db.employee.update({id:1},{$set:{firstName:"ankit_UPDATED"}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })


Let’s understand meaning of statement
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
"nMatched" : 1 shows that there was 1 result found corresponding to id=1 and
"nModified" : 1 shows that there was 1 document modified.

Now let's display documents of collection after update >
> db.employee.find();
{ "_id" : ObjectId("584ebed11127dea5ece72742"), "id" : 1, "firstName" : "ankit_UPDATED" }
{ "_id" : ObjectId("584ebee21127dea5ece72743"), "id" : 2, "firstName" : "sam" }

3) UPDATE Example2 in MongoDB >
Let’s UPDATE id where firstName= "sam" >
> db.employee.update({firstName:"sam"},{$set:{id:22}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : "sam" })


Now, let's display documents of collection after update >
> db.employee.find();
{ "_id" : ObjectId("584ebed11127dea5ece72742"), "id" : 1, "firstName" : "ankit_UPDATED" }
{ "_id" : ObjectId("584ebee21127dea5ece72743"), "id" : 22, "firstName" : "sam" }

4) SUMMARY>
So in this mongoDB tutorial we learned how to Update documents in collection in mongoDB.
UPDATE Example1 in MongoDB >
Let’s UPDATE firstname where id=1 >
> db.employee.update({id:1},{$set:{firstName:"ankit_UPDATED"}})


UPDATE Example2 in MongoDB >
Let’s UPDATE id where firstName= "sam" >
> db.employee.update({firstName:"sam"},{$set:{id:22}})


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RELATED LINKS>

What is MongoDB - A quick introduction to database

objectId in MongoDB

Create new database in mongoDB

Create new collection(table) in mongoDB

Data Modelling in MongoDB - Multiple tables


Delete documents in collection (table) in mongoDB

Labels: MongoDB
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