Handling Indexes

This is an introduction to ArangoDB's interface for indexs in general. There are special sections for cap constraints, geo-spatial indexes, hash indexes, and skip-lists.

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• Handling Indexes
  • Indexes, Identifiers, Handles
  • Address and ETag of an Index
  • Working with Indexes
    • Collection Methods
      • collection.index
      • collection.getIndexes
      • collection.dropIndex
    • Database Methods
      • db._index
      • db._dropIndex

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Indexes, Identifiers, Handles

Index: Indexes are used to allow fast access to documents. For each collection there is always the primary index which is a hash index for the document identifier.

Index Handle: An index handle uniquely identifies an index in the database. It is a string and consists of a collection identifier and a index identifier separated by /.

Geo Index: A geo index is used to find places on the surface of the earth fast.

Hash Index: A hash index is used to find documents based on examples.

Skiplist Index: A skiplist is used to find ranges of documents.

Address and ETag of an Index

All indexs in ArangoDB have an index handle. This handle uniquely defines an index and is managed by ArangoDB. The interface allows you to access the indexs of a collection as:

db.collection.index(index-handle)

For example: Assume that the index handle, which is stored in the _id field of the index, is 7254820/362549736 and the index lives in a collection named demo, then that index can be accessed as:

db.demo.index("7254820/362549736")

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

db._index("7254820/362549736")

Working with Indexes

Collection Methods

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collection.index(index-handle)

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Returns the index with index-handle or null if no such index exists.

Examples

arango> db.example.getIndexes().map(function(x) { return x.id; });
["93013/0"]
arango> db.example.index("93013/0");
{ "id" : "93013/0", "type" : "primary", "fields" : ["_id"] }

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getIndexes()

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Returns a list of all indexes defined for the collection.

Examples

arango> db.demo.getIndexes()
[
  { "id" : "1439003/0", 
    "type" : "primary",
    "fields" : ["_id"]
  }, 
  { 
    "id" : "1439003/2290971", 
    "unique" : true, 
    "type" : "hash", 
    "fields" : ["a"] 
  }, 
  { 
    "id" : "1439003/2946331",
    "unique" : false, 
    "type" : "hash", 
    "fields" : ["b"] 
  },
  { 
    "id" : "1439003/3077403", 
    "unique" : false, 
    "type" : "skiplist", 
    "fields" : ["c"]
  }
]

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collection.dropIndex(index)

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Drops the index. If the index does not exist, then false is returned. If the index existed and was dropped, then true is returned. Note that you cannot drop the primary index.

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collection.dropIndex(index-handle)

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Same as above. Instead of an index an index handle can be given.

Examples

arango> db.example.ensureSkiplist("a", "b");
{ "id" : "73650/991154", "unique" : false, "type" : "skiplist", "fields" : ["a", "b"], "isNewlyCreated" : true }

arango> i = db.example.getIndexes();
[{ "id" : "73650/0", "type" : "primary", "fields" : ["_id"] },
 { "id" : "73650/991154", "unique" : false, "type" : "skiplist", "fields" : ["a", "b"] }]

arango> db.example.dropIndex(i[0])
false

arango> db.example.dropIndex(i[1].id)
true

arango> i = db.example.getIndexes();
[{ "id" : "73650/0", "type" : "primary", "fields" : ["_id"] }]

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Database Methods

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db._index(index-handle)

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Returns the index with index-handle or null if no such index exists.

Examples

arango> db.example.getIndexes().map(function(x) { return x.id; });
["93013/0"]
arango> db._index("93013/0");
{ "id" : "93013/0", "type" : "primary", "fields" : ["_id"] }

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db._dropIndex(index)

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Drops the index. If the index does not exists, then false is returned. If the index existed and was dropped, then true is returned. Note that you cannot drop the primary index.

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db._dropIndex(index-handle)

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Drops the index with index-handle.

Examples

arango> db.example.ensureSkiplist("a", "b");
{ "id" : "73650/1577138", "unique" : false, "type" : "skiplist", "fields" : ["a", "b"], "isNewlyCreated" : true }

arango> i = db.example.getIndexes();
[{ "id" : "73650/0", "type" : "primary", "fields" : ["_id"] },
 { "id" : "73650/1577138", "unique" : false, "type" : "skiplist", "fields" : ["a", "b"] }]

arango> db._dropIndex(i[0]);
false

arango> db._dropIndex(i[1].id);
true

arango> i = db.example.getIndexes();
[{ "id" : "73650/0", "type" : "primary", "fields" : ["_id"] }]