Question 118483 in Mongodb Question posted in
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Mongodb – How to make a unique number in the _id

Unfortunately, I can’t figure out how to turn the _id ObjectID, into a _id with a unique number generated by a number.

For example:
Right now the generation is like this

[
{
 _id: 'adioj2ouro21jr9o3',
 // ...
}
]

And we need to

[
{
 id: 1,
 // ...
}
]
Tags:

2

Answers


  1. 0

    https://www.mongodb.com/basics/mongodb-auto-increment

    I have not used mongoDB myself. It appears that mongoDB doesnt support auto increment like MySQL would.

    Could you use javascript to add N+1 on the last id in the table and manually create the ID field as needed?

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  2. 0

    1. The build-in mechanism in mongoDB to auto generate ObjectId() is a very good and easy way to have unique _id and also contain the insertion date which sometimes make troubleshooting easier.

    2. You cannot replace having default _id key with id , but you can have both _id and id …

    3. However you can insert different document in _id instead of the default ObjectId().

    4. if you want the _id to be number you can read max(_id) and insert new document with inc(max(_id)) but this is not scalalble solution since if your writes increase it can become a bottleneck at some point.

    Finally it is recomended to leave the default ObjectId() as your auto generated _id …

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