A. How do I index nested and all of it's values?
B. How do I index valuetwo?
{
id: 00000,
attrs: {
nested:{
value: value1,
valuetwo: value2,
}
}
}
I've looked here: http://www.mongodb.org/display/DOCS/Indexes, and the docs to my knowledge, aren't clear about indexing things that aren't nested.
You'd create them just as if you were creating an index on a top level field:
db.collection.createIndex({"attrs.nested.value": 1})
You do need to explicitly create indexes on each field.
MongoDB automatically creates a multikey index if any indexed field is an array; you do not need to explicitly specify the multikey type.
This will work for both the scenario's
db.coll.createIndex( { "addr.pin": 1 } )
Scenario 1 nested OBJECTS
{
userid: "1234",
addr: {
pin:"455522"
}
},
{
userid: "1234",
addr: {
pin:"777777"
}
}
Scenario 2 nested Arrays
{
userid: "1234",
addr: [
{ pin:"455522" },
{ pin:"777777" },
]
}
A. to index all the properties in "nested" you will have to index them separately:
db.collection.createIndex({"attrs.nested.value": 1});
db.collection.createIndex({"attrs.nested.valuetwo": 1});
This can be done in one command with:
db.collection.createIndexes([{"attrs.nested.value": 1}, {"attrs.nested.valuetwo": 1}]);
B. to index just "valuetwo":
db.collection.createIndex({"attrs.nested.valuetwo": 1})
Use createIndex over ensureIndex as ensureIndex is Deprecated since version 3.0.0
value and valuetwo. The second creates a single compound index on both of these values. This index can only be used for queries which specify a value for value. That is, it's not useful for queries on valuetwo alone.
db.collection.createIndexes([{"attrs.nested.value": 1}, {"attrs.nested.valuetwo": 1}]);createIndexes. I edited the answer to use this.It looks like there may have been a new feature to address this since these answers have been written.
Mongodb has wildcard indexes that allow you to create an index for a field that contains varying keys.
From the documentation:
If the field is a nested document or array, the wildcard index recurses into the document/array and indexes all scalar fields in the document/array.
So the index in the question would be constructed like this:
db.collections.createIndex({ "attrs.nested.$**": 1 })
You can read more about this here!
The previous answers nearly gave me a heart attack.
