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updated array index documentation

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Jan Steemann 2015-11-26 14:08:52 +01:00
parent 1a23993f99
commit 27c319b31c
1 changed files with 7 additions and 1 deletions
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8
Documentation/Books/Users/IndexHandling/IndexBasics.mdpp
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@ -269,7 +269,8 @@ way.
To make an index insert the individual array members into the index instead of the entire array
value, a special array index needs to be created for the attribute. Array indexes can be set up
like regular hash or skiplist indexes using the `collection.ensureIndex()` function. To make a
hash or skiplist index an array index, the index attribute name needs to be extended with <i>[\*]</i>.
hash or skiplist index an array index, the index attribute name needs to be extended with <i>[\*]</i>
when creating the index and when filtering in an AQL query using the `IN` operator.
The following example creates an array hash index on the `tags` attribute in a collection named
`posts`:
@ -369,3 +370,8 @@ db.posts.insert({tags: [1, 2, 3], name: "alice"})
db.posts.insert({tags: [null], name: "bob"})
// Will be indexed for [null, "bob"]
```
Please note that filtering using array indexes only works from within AQL queries and
only if the query filters on the indexed attribute using the `IN` operator. The other
comparison operators (`==`, `!=`, `>`, `>=`, `<`, `<=`) currently cannot use array
indexes.