!CHAPTER Working with Indexes

!SECTION Index Identifiers and Handles 

An *index handle* uniquely identifies an index in the database. It is a string and 
consists of the collection name and an *index identifier* separated by a `/`. The 
index identifier part is a numeric value that is auto-generated by ArangoDB.

A specific index of a collection can be accessed using its *index handle* or
*index identifier* as follows:

```js
db.collection.index("<index-handle>");
db.collection.index("<index-identifier>");
db._index("<index-handle>");
```

For example: Assume that the index handle, which is stored in the `_id`
attribute of the index, is `demo/362549736` and the index was created in a collection
named `demo`. Then this index can be accessed as:

```js
db.demo.index("demo/362549736");
```

Because the index handle is unique within the database, you can leave out the
*collection* and use the shortcut:

```js
db._index("demo/362549736");
```

!SECTION Collection Methods

!SUBSECTION Listing all indexes of a collection
<!-- arangod/V8Server/v8-vocindex.cpp -->
@startDocuBlock collectionGetIndexes

!SUBSECTION Creating an index
Indexes should be created using the general method *ensureIndex*. This
method obsoletes the specialized index-specific methods *ensureHashIndex*,
*ensureSkiplist*, *ensureUniqueConstraint* etc.

<!-- arangod/V8Server/v8-vocindex.cpp -->
@startDocuBlock collectionEnsureIndex

!SUBSECTION Dropping an index
<!-- arangod/V8Server/v8-vocindex.cpp -->
@startDocuBlock col_dropIndex

!SECTION Database Methods

!SUBSECTION Fetching an index by handle
<!-- js/server/modules/@arangodb/arango-database.js -->
@startDocuBlock IndexHandle

!SUBSECTION Dropping an index
<!-- js/server/modules/@arangodb/arango-database.js -->
@startDocuBlock dropIndex

!SUBSECTION Revalidating whether an index is used
<!-- js/server/modules/@arangodb/arango-database.js -->
@startDocuBlock IndexVerify