Second parameter of db.col.createIndex

Working with Data
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1

Could someone explain to me exactly what this index means or implies?

db.x.createIndex( { “user.login”: 1, “user.date”: -1 }, “myIndex” )

The second parameter “myIndex” catches my attention and I don’t understand where to find this kind of thing in the mongo guide. Any reference?

Thank you!

2

The first parameter is specifying the shape of the compound index. First, by sorting embedded field user.login in ascending (1) order, and then by sorting user.date in descending (-1) order within the context of user.login. The field order and the direction ( 1 or -1) of sort is important in a compound index.

The second parameter to the createIndex function (https://docs.mongodb.com/manual/reference/method/db.collection.createIndex/#options-for-all-index-types) is the name of the index.

Thanks,
Mahi

1 Like
3

Thank you very much, I really couldn’t find the logic, I already read “options for all index types” → name