MONGO study notes (iii)

First, the index

Db.person.remove ({})
for (Var i=0;i<100000;i++) {
var rand = parseint (I*math.random ());
Db.person.insert ({"Name": "XX" +i, "age": Rand})
}

Db.person.find ({"Name": "XX" +1000}). Explain ()

Stage is Collscan description does not go index, walk index words will show IXSCAN

<1> Building an Index
Db.person.ensureIndex ({"Name": 1})

Here we use the Ensureindex to build an index on name. "1": Indicates ascending by name, "1": Indicates descending by name.

<2> View Index
Db.person.getIndexes ()

<3> Delete an index
Db.person.dropIndex ({"Name": 1})

<4> Unique Index
Db.person.ensureIndex ({"Name": 1},{"unique": true})

<5> Combined Index
Db.person.ensureIndex ({"Name": 1, "Birthday": 1})

MONGO study notes (iii)