MongoDB provides db.myCollection.update() method to update or modify document. Also you can use db.myCollection.save() method to upsert document. Means update() and save() methods use to update/modify document.
Syntax of update() method
The syntax of the update() method is given below.
db.Collection_Name.update(Selecttion_Criteria,Updated_Date)
|
Example
Suppose we have a collection of EMP as like below.
/* 1 */
{
"_id" : ObjectId("584a7c33309356d26bef176e"),
"Name" : "Dilip",
"Salary" : 50000.0,
"Project" : "Codeafri Mongodb",
"DOJ" : ISODate("2014-12-01T20:19:55.782Z")
}
/* 2 */
{
"_id" : ObjectId("584a7c33309356d26bef176f"),
"Name" : "Vipul",
"Salary" : 30000.0,
"Project" : "Codeafri UI",
"DOJ" : ISODate("2015-11-01T20:19:55.782Z")
}
/* 3 */
{
"_id" : ObjectId("584a7c33309356d26bef1770"),
"Name" : "Ashish",
"Salary" : 100000.0,
"Project" : "Codeafri Project architect",
"DOJ" : ISODate("2013-10-01T20:19:55.782Z")
}
|
Suppose we want to modify Salary of Dilip from 50000 to 70000, now we can update salary executing the following command.
>db.EMP.update({'Name':'Dilip'},{$set:{'Salary':70000}})
|
Find Updated Records
>db.EMP.find()
|
Output
/* 1 */
{
"_id" : ObjectId("584a7c33309356d26bef176e"),
"Name" : "Dilip",
"Salary" : 70000.0,
"Project" : "Codeafri Mongodb",
"DOJ" : ISODate("2014-12-01T20:19:55.782Z")
}
/* 2 */
{
"_id" : ObjectId("584a7c33309356d26bef176f"),
"Name" : "Vipul",
"Salary" : 30000.0,
"Project" : "Codeafri UI",
"DOJ" : ISODate("2015-11-01T20:19:55.782Z")
}
/* 3 */
{
"_id" : ObjectId("584a7c33309356d26bef1770"),
"Name" : "Ashish",
"Salary" : 100000.0,
"Project" : "Codeafri Project architect",
"DOJ" : ISODate("2013-10-01T20:19:55.782Z")
}
|
You can see in output (bold) Salary of Dilip has been updated with 70000.
Syntax of save() method
db.COLLECTION_NAME.save({_id:ObjectId(),NEW_DATA})
|
Save() methods replaces the existing document with a new document.
Example
Suppose we have an employee collection EMP as below.
/* 1 */
{
"_id" : ObjectId("584a7ec1309356d26bef1771"),
"Name" : "Dilip",
"Salary" : 50000.0,
"Project" : "Codeafri Mongodb",
"DOJ" : ISODate("2014-12-01T20:19:55.782Z")
}
/* 2 */
{
"_id" : ObjectId("584a7ec1309356d26bef1772"),
"Name" : "Vipul",
"Salary" : 30000.0,
"Project" : "Codeafri UI",
"DOJ" : ISODate("2015-11-01T20:19:55.782Z")
}
/* 3 */
{
"_id" : ObjectId("584a7ec1309356d26bef1773"),
"Name" : "Ashish",
"Salary" : 100000.0,
"Project" : "Codeafri Project architect",
"DOJ" : ISODate("2013-10-01T20:19:55.782Z")
}
|
Due to some reason we want to replace Dilip’s document with another document. Here we can use save() method, please see the following command
db.EMP.save(
{
"_id" : ObjectId("584a7ec1309356d26bef1771"),
"Name":"Dilip Kumar Singh",
"Salary":90000,
"Project":"Codeafri Mongodb, Mongodb atlas",
"DOJ":ISODate("2016-12-01T20:19:55.782Z")
}
)
|
Find updated records
db.EMP.find()
|
Output
/* 1 */
{
"_id" : ObjectId("584a7ec1309356d26bef1772"),
"Name" : "Vipul",
"Salary" : 30000.0,
"Project" : "Codeafri UI",
"DOJ" : ISODate("2015-11-01T20:19:55.782Z")
}
/* 2 */
{
"_id" : ObjectId("584a7ec1309356d26bef1773"),
"Name" : "Ashish",
"Salary" : 100000.0,
"Project" : "Codeafri Project architect",
"DOJ" : ISODate("2013-10-01T20:19:55.782Z")
}
/* 3 */
{
"_id" : ObjectId("584a7ec1309356d26bef1771"),
"Name" : "Dilip Kumar Singh",
"Salary" : 90000.0,
"Project" : "Codeafri Mongodb, Mongodb atlas",
"DOJ" : ISODate("2016-12-01T20:19:55.782Z")
}
|
You can see the bold document in output which is a newly replaced document.
