How do I create an indexes for "date"?

Question

CentOS7, MongoDB server version: 3.4.2

db.animals.createIndex('date')
{
    "ok" : 0,
    "errmsg" : "The field 'key' must be an object, but got string",
    "code" : 14,
    "codeName" : "TypeMismatch"
}

db.animals.find({}, {date: 1}).limit(1)
{ "_id" : 3477, "date" : ISODate("2016-12-22T09:38:59Z") }

Atish · Accepted Answer · 2017-03-19T14:24:41.443

42

You can create simple index on key date using:

Ascending order: db.animals.createIndex({'date':1})

Descending order: db.animals.createIndex({'date':-1})

You may need to take a look at indexing doc before adding indexes

edited Mar 19 '17 at 14:24

answered Mar 19 '17 at 14:18

Atish

4,277
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1

when should i use 1 rather than -1? – Jeremias Nater Jan 12 '22 at 14:58

score 8 · Answer 2 · answered Oct 22 '18 at 15:23

8

for single field you don't need to reverse the index as mongodb can use the index in either direction. It should only matter when you have a compound index and you have a sort going in different directions.

answered Oct 22 '18 at 15:23

Dwayne Mcnab

131
1
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How do I create an indexes for "date"?

2 Answers2

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