2
You can do this, every time I create a new user for example it auto increments _id. Starting from 1 and going up to the number of users
2
You can do this, every time I create a new user for example it auto increments _id. Starting from 1 and going up to the number of users
4
Yes, following the example of documentation(create-an-auto-incrementing-field), it would be something like that:
1 - Enter the starting value for the field in the meter collection:
db.counters.insert(
{
_id: "userid",
seq: 0
}
)
2 - Create a function getNextSequence
which accepts a sequence name. The function uses the method findAndModify()
to atomically increment the value seq
and return this new value:
function getNextSequence(name) {
var ret = db.counters.findAndModify(
{
query: { _id: name },
update: { $inc: { seq: 1 } },
new: true
}
);
return ret.seq;
}
3 - Use this function getNextSequence()
during insertion.
db.users.insert(
{
_id: getNextSequence("userid"),
name: "Sarah C."
}
)
db.users.insert(
{
_id: getNextSequence("userid"),
name: "Bob D."
}
)
More information see the documentation.
1
Mongodb’s own documentation has an example and shows you how to do it. Even they say that the method used is more recommended for the _id, just what you need. Give a look HERE.
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https://docs.mongodb.com/v2.8/tutorial/create-an-auto-incrementing-field/
– Maniero