The collection object of the JavaScript API

Collection objects represent document collections and provide access to information and methods for executing collection-related operations

The JavaScript API returns collection objects when you use the following methods of the db object from the @arangodb:

  • db._create(...)
  • db._createDocumentCollection(...)
  • db._createEdgeCollection(...)
  • db._collections(...)
  • db._collection(...)
Square brackets in function signatures denote optional arguments.

Collection

collection.checksum([withRevisions [, withData]])

Calculate a checksum for the data in a collection:

The checksum operation calculates an aggregate hash value for all document keys contained in collection collection.

If the optional argument withRevisions is set to true, then the revision ids of the documents are also included in the hash calculation.

If the optional argument withData is set to true, then all user-defined document attributes are also checksummed. Including the document data in checksumming makes the calculation slower, but is more accurate.

collection.compact()

Compacts the data of a collection in order to reclaim disk space. The operation compacts the document and index data by rewriting the underlying .sst files and only keeps the relevant entries.

Under normal circumstances running a compact operation is not necessary, as the collection data is eventually compacted anyway. However, in some situations, e.g. after running lots of update/replace or remove operations, the disk data for a collection may contain a lot of outdated data for which the space shall be reclaimed. In this case the compaction operation can be used.

collection.drop([options])

Drops a collection and all its indexes and data. In order to drop a system collection, an options object with attribute isSystem set to true must be specified.

Dropping a collection in a cluster, which is prototype for sharing in other collections is prohibited. In order to be able to drop such a collection, all dependent collections must be dropped first.

Examples

Drop a collection:

var coll = db.example;
coll.drop();
coll;
Show output

Drop a system collection:

var coll = db._example;
coll.drop({ isSystem: true });
Show output

collection.figures([details])

Returns an object containing statistics about the collection.

Setting details to true returns extended storage engine-specific details to the figures (introduced in v3.8.0). The details are intended for debugging ArangoDB itself and their format is subject to change. By default, details is set to false, so no details are returned and the behavior is identical to previous versions of ArangoDB.

  • indexes.count: The total number of indexes defined for the collection, including the pre-defined indexes (e.g. primary index).
  • indexes.size: The total memory allocated for indexes in bytes.
  • documentsSize
  • cacheInUse
  • cacheSize
  • cacheUsage

Examples

Get the basic collection figures:

db.demo.figures()
Show output

Get the detailed collection figures:

db.demo.figures(true)
Show output

collection.getResponsibleShard(document)

Return the responsible shard for the given document.

Returns a string with the responsible shard’s ID. Note that the returned shard ID is the ID of responsible shard for the document’s shard key values, and it returns even if no such document exists.

The getResponsibleShard() method can only be used on Coordinators in clusters.

collection.load()

Loads a collection into memory.

Cluster collections are loaded at all times.
The load() function is deprecated as of ArangoDB 3.8.0. The function may be removed in future versions of ArangoDB. There should not be any need to load a collection with the RocksDB storage engine.

collection.name()

Returns the name of the collection as a string.

Examples

Get the collection name from a collection object:

var coll = db._create("example");
coll.name();

collection.properties([properties])

Get or set the properties of a collection.

collection.properties()

Returns an object containing all collection properties.

  • waitForSync (boolean): If true, creating, changing, or removing documents waits until the data has been synchronized to disk.

  • keyOptions (object): An object which contains key generation options.

    • type (string): Specifies the type of the key generator. Possible values:

      • "traditional"
      • "autoincrement"
      • "uuid"
      • "padded"
    • allowUserKeys (boolean): If set to true, then you are allowed to supply own key values in the _key attribute of documents. If set to false, then the key generator is solely responsible for generating keys and an error is raised if you supply own key values in the _key attribute of documents.

      You should not use both user-specified and automatically generated document keys in the same collection in cluster deployments for collections with more than a single shard. Mixing the two can lead to conflicts because Coordinators that auto-generate keys in this case are not aware of all keys which are already used.
    • increment (number): The increment value for the autoincrement key generator. Not used for other key generator types.

    • offset (number): The initial offset value for the autoincrement key generator. Not used for other key generator types.

    • lastValue (number): the current offset value of the autoincrement or padded key generator. This an internal property for restoring dumps properly.

  • schema (object|null): An object that specifies the collection-level document schema for documents. The attribute keys rule, level and message must follow the rules documented in Document Schema Validation

  • computedValues (array|null): An array of objects, each representing a Computed Value.

  • cacheEnabled (boolean): Whether the in-memory hash cache for documents is enabled for this collection (default: false).

  • isSystem (boolean): Whether the collection is a system collection. Collection names that starts with an underscore are usually system collections.

  • syncByRevision (boolean): Whether the newer revision-based replication protocol is enabled for this collection. This is an internal property.

  • globallyUniqueId (string): A unique identifier of the collection. This is an internal property.

In a cluster setup, the result also contains the following attributes:

  • numberOfShards (number): The number of shards of the collection.

  • shardKeys (array): Contains the names of document attributes that are used to determine the target shard for documents.

  • replicationFactor (number|string): Determines how many copies of each shard are kept on different DB-Servers. Has to be in the range of 1-10 or the string "satellite" for a SatelliteCollection (Enterprise Edition only). (cluster only)

  • writeConcern (number): Determines how many copies of each shard are required to be in sync on the different DB-Servers. If there are less then these many copies in the cluster, a shard refuses to write. Writes to shards with enough up-to-date copies succeed at the same time, however. The value of writeConcern cannot be greater than replicationFactor. (cluster only)

  • shardingStrategy (string): the sharding strategy selected for the collection. (cluster only)

    Possible values:

    • "community-compat"
    • "enterprise-compat"
    • "enterprise-smart-edge-compat"
    • "hash"
    • "enterprise-hash-smart-edge"
    • "enterprise-hex-smart-vertex"
  • distributeShardsLike (string): The name of another collection. This collection uses the replicationFactor, numberOfShards and shardingStrategy properties of the other collection and the shards of this collection are distributed in the same way as the shards of the other collection.

  • isSmart (boolean): Whether the collection is used in a SmartGraph or EnterpriseGraph (Enterprise Edition only). This is an internal property.

  • isDisjoint (boolean): Whether the SmartGraph this collection belongs to is disjoint (Enterprise Edition only). This is an internal property.

  • smartGraphAttribute (string): The attribute that is used for sharding: vertices with the same value of this attribute are placed in the same shard. All vertices are required to have this attribute set and it has to be a string. Edges derive the attribute from their connected vertices.

    This feature can only be used in the Enterprise Edition.

  • smartJoinAttribute (string): In an Enterprise Edition cluster, this attribute determines an attribute of the collection that must contain the shard key value of the referred-to SmartJoin collection.


collection.properties(properties)

Changes the collection properties. properties must be an object and can have one or more of the following attribute(s):

  • waitForSync (boolean): If true, creating a document only returns after the data was synced to disk.

  • replicationFactor (number|string): Change the number of shard copies kept on different DB-Servers. Valid values are integer numbers in the range of 1-10 or the string "satellite" for a SatelliteCollection (Enterprise Edition only). (cluster only)

  • writeConcern (number): Change how many copies of each shard are required to be in sync on the different DB-Servers. If there are less then these many copies in the cluster, a shard refuses to write. Writes to shards with enough up-to-date copies succeed at the same time however. The value of writeConcern cannot be greater than replicationFactor. (cluster only)

  • computedValues (array|null): An array of objects, each representing a Computed Value.

  • schema (object|null): An object that specifies the collection level document schema for documents. The attribute keys rule, level and message must follow the rules documented in Document Schema Validation

  • cacheEnabled (boolean): Whether the in-memory hash cache for documents should be enabled for this collection. Can be controlled globally with the --cache.size startup option. The cache can speed up repeated reads of the same documents via their document keys. If the same documents are not fetched often or are modified frequently, then you may disable the cache to avoid the maintenance costs.

Some other collection properties, such as type, keyOptions, numberOfShards or shardingStrategy cannot be changed once the collection is created.

Examples

Read all properties:

db.example.properties();
Show output

Change a property:

db.example.properties({ waitForSync : true });
Show output

collection.rename(name)

Renames a collection. The new-name must not already be used for a different collection. new-name must also be a valid collection name. For information about the naming constraints for collections, see Collection names.

If renaming fails for any reason, an error is thrown. If renaming the collection succeeds, then the collection is also renamed in all graph definitions inside the _graphs collection in the current database.

The rename() method cannot be used in clusters.

Examples

var coll = db.example;
coll.rename("better-example");
coll;
Show output

collection.revision()

Returns the revision ID of the collection

The revision ID is updated when the document data is modified, either by inserting, deleting, updating or replacing documents in it.

The revision ID of a collection can be used by clients to check whether data in a collection has changed or if it is still unmodified since a previous fetch of the revision ID.

The revision ID returned is a string value. Clients should treat this value as an opaque string, and only use it for equality/non-equality comparisons.

collection.shards([details])

Return the available shards for the collection.

If details is not set, or set to false, returns an array with the names of the available shards of the collection.

If details is set to true, returns an object with the shard names as object attribute keys, and the responsible servers as an array mapped to each shard attribute key.

The leader shards are always first in the arrays of responsible servers.

The shards() method can only be used on Coordinators in clusters.

collection.truncate()

Truncates a collection, removing all documents but keeping all its indexes.

Examples

Truncates a collection:

var coll = db.example;
var doc = coll.save({ "Hello" : "World" });
coll.count();
coll.truncate();
coll.count();

collection.type()

Returns the type of a collection. Possible values are:

  • 2: document collection
  • 3: edge collection

collection.unload()

Starts unloading a collection from memory. Note that unloading is deferred until all queries have finished.

In cluster deployments, collections cannot be unloaded.
The unload() function is deprecated as of ArangoDB 3.8.0. The function may be removed in future versions of ArangoDB. There should not be any need to unload a collection with the RocksDB storage engine.

Indexes

collection.ensureIndex(description)

Creates an index if it doesn’t exist already.

See collection.ensureIndex().

collection.indexes([withStats [, withHidden]])

Lists all indexes of the collection.

See collection.indexes().

collection.getIndexes([withStats [, withHidden]])

Same as collection.indexes([withStats [, withHidden]]).

collection.index(index)

Gets an index by identifier.

See collection.index().

collection.dropIndex(index)

Drops an index by identifier.

See collection.dropIndex().

Documents

collection.all()

Fetches all documents from a collection and returns a cursor. You can use toArray(), next(), or hasNext() to access the result. The result can be limited using the skip() and limit() operator.

Examples

Use toArray() to get all documents at once:

var docs = db.five.insert([
  { name : "one" },
  { name : "two" },
  { name : "three" },
  { name : "four" },
  { name : "five" }
]);
db.five.all().toArray();
Show output

Use limit() to restrict the documents:

var docs = db.five.insert([
  { name : "one" },
  { name : "two" },
  { name : "three" },
  { name : "four" },
  { name : "five" }
]);
db.five.all().limit(2).toArray();
Show output

collection.any()

Returns a random document from the collection or null if none exists.

Note: This is generally an expensive operation for the RocksDB storage engine but ArangoDB uses an optimization for retrieving a single pseudo-random document.

collection.byExample(example)

Fetches all documents from a collection that match the specified example and returns a cursor.

You can use toArray(), next(), or hasNext() to access the result. The result can be limited using the skip() and limit() operator.

An attribute name of the form a.b is interpreted as attribute path, not as attribute. If you use

{ "a" : { "c" : 1 } }

as example, then you will find all documents, such that the attribute a contains a document of the form { "c" : 1 }. For example the document

{ "a" : { "c" : 1 }, "b" : 1 }

will match, but the document

{ "a" : { "c" : 1, "b" : 1 } }

will not.

However, if you use

{ "a.c" : 1 }

then you will find all documents, which contain a sub-document in a that has an attribute c of value 1. Both the following documents

{ "a" : { "c" : 1 }, "b" : 1 }

and

{ "a" : { "c" : 1, "b" : 1 } }

will match.

collection.byExample(path1, value1, ...)

As alternative you can supply an array of paths and values.

Examples

Use toArray() to get all documents at once:

db.users.insert([
  { name: "Gerhard" },
  { name: "Helmut" },
  { name: "Angela" }
]);
db.users.all().toArray();
db.users.byExample({ "_id" : "users/20" }).toArray();
db.users.byExample({ "name" : "Gerhard" }).toArray();
db.users.byExample({ "name" : "Helmut", "_id" : "users/15" }).toArray();
Show output

Use next() to loop over all documents:

db.users.insert([
  { name: "Gerhard" },
  { name: "Helmut" },
  { name: "Angela" }
]);
var cursor = db.users.byExample( {"name" : "Angela" } );
while (cursor.hasNext()) {
  print(cursor.next());
}
Show output

collection.count()

Returns the number of living documents in the collection.

Examples

db.users.count();

collection.document(object [, options])

The document() method finds a document given an object object containing the _id or _key attribute. The method returns the document if it can be found. If both attributes are given, the _id takes precedence, it is an error, if the collection part of the _id does not match the collection.

An error is thrown if _rev is specified but the document found has a different revision already. An error is also thrown if no document exists with the given _id or _key value.

Please note that if the method is executed on the arangod server (e.g. from inside a Foxx application), an immutable document object will be returned for performance reasons. It is not possible to change attributes of this immutable object. To update or patch the returned document, it needs to be cloned/copied into a regular JavaScript object first. This is not necessary if the document method is called from out of arangosh or from any other client.

If you pass options as the second argument, it must be an object.

  • If the object has the allowDirtyReads attribute set to true, then the Coordinator is allowed to read from any shard replica and not only from the leader shard. See Read from followers for details.

collection.document(document-identifier [, options])

Finds a document using a document identifier, optionally with an options passed as an object.

No revision can be specified in this case.


collection.document(document-key [, options])

Finds a document using a document key, optionally with an options passed as an object.

No revision can be specified in this case.


collection.document(array [, options])

This variant allows you to perform the operation on a whole array of arguments. The behavior is exactly as if document() would have been called on all members of the array separately and all results are returned in an array. If an error occurs with any of the documents, no exception is raised! Instead of a document, an error object is returned in the result array.

Examples

Return a document using a document identifier:

db.example.document("example/2873916");
Show output

Return a document using a document key:

db.example.document("2873916");
Show output

Return a document using an object with a document identifier:

db.example.document({_id: "example/2873916"});
Show output

Return multiple documents using an array of document keys:

db.example.document(["2873916","2873917"]);
Show output

An error is raised if the document is unknown:

db.example.document("example/4472917"); 
Show output

An error is raised if the document key or identifier is invalid:

db.example.document(""); 
Show output

collection.documents(keys)

Looks up the documents in the specified collection using the array of keys provided. All documents for which a matching key was specified in the keys array and that exist in the collection will be returned. Keys for which no document can be found in the underlying collection are ignored, and no exception will be thrown for them.

This method is deprecated in favor of the array variant of document().

Examples

var keys = [ ];
for (var i = 0; i < 5; ++i) {
  db.example.insert({ _key: "test" + i, value: i });
  keys.push("test" + i);
}
db.example.documents(keys);
Show output

collection.documentId(documentKey)

Converts a document key to a document identifier by prepending the collection’s name and a forward slash to the key.

Raises an error if the document key is invalid. Note that this method does not check whether the document exists in the collection.

collection.exists(object [, options])

The exists() method determines whether a document exists given an object object containing the _id or _key attribute. If both attributes are given, the _id takes precedence, it is an error, if the collection part of the _id does not match the collection.

An error is thrown if _rev is specified but the document found has a different revision already.

Instead of returning the found document or an error, this method will only return an object with the attributes _id, _key and _rev, or false if no document with the given _id or _key exists. It can thus be used for easy existence checks.

This method throws an error if used improperly, e.g. if called with a string that isn’t a document key or identifier, an object with invalid or missing _key or _id attribute, or if documents from other collections are requested.

If you pass options as the second argument, it must be an object. If this object has the allowDirtyReads attribute set to true, then the Coordinator is allowed to read from any shard replica and not only from the leader shard. See Read from followers for details.


collection.exists(document-identifier [, options])

Checks whether a document exists described by a document identifier, optionally with options passed as an object.

No revision can be specified in this case.


collection.exists(document-key [, options])

Checks whether a document exists described by a document key, optionally with options passed as an object.

No revision can be specified in this case.


collection.exists(array [, options])

This variant allows you to perform the operation on a whole array of arguments. The behavior is exactly as if exists() would have been called on all members of the array separately and all results are returned in an array. If an error occurs with any of the documents, the operation stops immediately returning only an error object.

collection.firstExample(example)

Returns some document of a collection that matches the specified example. If no such document exists, null will be returned. The example has to be specified as paths and values. See byExample for details.


collection.firstExample(path1, value1, ...)

As alternative you can supply an array of paths and values.

Examples

db.users.firstExample("name", "Angela");
Show output

collection.insert(data [, options])

Creates a new document in the collection from the given data. The data must be an object. The attributes _id and _rev are ignored and are automatically generated. A unique value for the attribute _key will be automatically generated if not specified. If specified, there must not be a document with the given _key in the collection.

The method returns a document with the attributes _id, _key and _rev. The attribute _id contains the document identifier of the newly created document, the attribute _key the document key and the attribute _rev contains the document revision.


collection.insert(data, options)

Creates a new document in the collection from the given data as above. The optional options parameter must be an object and can be used to specify the following options:

  • waitForSync: One can force synchronization of the document creation operation to disk even in case that the waitForSync flag is been disabled for the entire collection. Thus, the waitForSync option can be used to force synchronization of just specific operations. To use this, set the waitForSync parameter to true. If the waitForSync parameter is not specified or set to false, then the collection’s default waitForSync behavior is applied. The waitForSync parameter cannot be used to disable synchronization for collections that have a default waitForSync value of true.
  • silent: If this flag is set to true, the method does not return any output.
  • returnNew: If this flag is set to true, the complete new document is returned in the output under the attribute new.
  • returnOld: If this flag is set to true, the complete old document is returned in the output under the attribute old. Only available in combination with the overwrite option
  • overwrite: If set to true, the insert becomes a replace-insert. If a document with the same _key exists already the new document is not rejected with unique constraint violated but will replace the old document. Note that operations with overwrite parameter require a _key attribute in the request payload, therefore they can only be performed on collections sharded by _key.
  • overwriteMode: this optional flag can have one of the following values:
    • ignore: if a document with the specified _key value exists already, nothing will be done and no write operation will be carried out. The insert operation will return success in this case. This mode does not support returning the old document version using the returnOld attribute. returnNew will only set the new attribute in the response if a new document was inserted.
    • replace: if a document with the specified _key value exists already, it will be overwritten with the specified document value. This mode will also be used when no overwrite mode is specified but the overwrite flag is set to true.
    • update: if a document with the specified _key value exists already, it will be patched (partially updated) with the specified document value. The overwrite mode can be further controlled via the keepNull and mergeObjects parameters.
    • conflict: if a document with the specified _key value exists already, return a unique constraint violation error so that the insert operation fails. This is also the default behavior in case the overwrite mode is not set, and the overwrite flag is false or not set either.
  • keepNull: The optional keepNull parameter can be used to modify the behavior when handling null values. Normally, null values are stored in the database. By setting the keepNull parameter to false, this behavior can be changed so that top-level attributes and sub-attributes in data with null values are removed from the target document (but not attributes of objects that are nested inside of arrays). This option controls the update-insert behavior only.
  • mergeObjects: Controls whether objects (not arrays) will be merged if present in both the existing and the patch document. If set to false, the value in the patch document will overwrite the existing document’s value. If set to true, objects will be merged. The default is true. This option controls the update-insert behavior only.

collection.insert(array [, options])

This variant allows you to perform the operation on a whole array of arguments. The behavior is exactly as if insert() would have been called on all members of the array separately and all results are returned in an array. If an error occurs with any of the documents, no exception is raised! Instead of a document, an error object is returned in the result array.

Examples

db.example.insert({ Hello : "World" });
db.example.insert({ Hello : "World" }, {waitForSync: true});
Show output

db.example.insert([{ Hello : "World" }, {Hello: "there"}])
db.example.insert([{ Hello : "World" }, {}], {waitForSync: true});
Show output

db.example.insert({ _key : "666", Hello : "World" });
db.example.insert({ _key : "666", Hello : "Universe" }, {overwrite: true, returnOld: true});
Show output

collection.iterate(iterator [, options])

The iterate() method is deprecated from version 3.11.0 onwards and will be removed in a future version.

Iterates over some elements of the collection and apply the function iterator to the elements. The function will be called with the document as first argument and the current number (starting with 0) as second argument.

options must be an object with the following attributes:

  • limit (optional, default none): use at most limit documents.

  • probability (optional, default all): a number between 0 and 1. Documents are chosen with this probability.

collection.remove(object)

Removes a document described by the object, which must be an object containing the _id or _key attribute. There must be a document with that _id or _key in the current collection. This document is then removed.

The method returns a document with the attributes _id, _key and _rev. The attribute _id contains the document identifier of the removed document, the attribute _rev contains the document revision of the removed document.

If the object contains a _rev attribute, the method first checks that the specified revision is the current revision of that document. If not, there is a conflict, and an error is thrown.


collection.remove(object, options)

Removes a document, with additional boolean options passed as an object:

  • waitForSync: One can force synchronization of the document creation operation to disk even in case that the waitForSync flag is been disabled for the entire collection. Thus, the waitForSync option can be used to force synchronization of just specific operations. To use this, set the waitForSync parameter to true. If the waitForSync parameter is not specified or set to false, then the collection’s default waitForSync behavior is applied. The waitForSync parameter cannot be used to disable synchronization for collections that have a default waitForSync value of true.
  • overwrite: If this flag is set to true, a _rev attribute in the object is ignored.
  • returnOld: If this flag is set to true, the complete previous revision of the document is returned in the output under the attribute old.
  • silent: If this flag is set to true, no output is returned.

collection.remove(document-identifier [, options])

Removes a document described by a document identifier, optionally with additional options passed as an object.

No revision check is performed.


collection.remove(document-key [, options])

Removes a document described by a document key, optionally with additional options passed as an object.

No revision check is performed.


collection.remove(array [, options])

This variant allows you to perform the operation on a whole array of document identifiers, document keys, and objects with a _key attribute.

The behavior is exactly as if remove() would have been called on all members of the array separately and all results are returned in an array. If an error occurs with any of the documents, no exception is raised! Instead of a document, an error object is returned in the result array.

Examples

Remove a document:

a1 = db.example.insert({ a : 1 });
db.example.document(a1);
db.example.remove(a1);
db.example.document(a1); 
Show output

Remove a document with a conflict:

a1 = db.example.insert({ a : 1 });
a2 = db.example.replace(a1, { a : 2 });
db.example.remove(a1);       
db.example.remove(a1, true);
db.example.document(a1);     
Show output

collection.removeByExample(example)

Removes all documents matching an example.


collection.removeByExample(document, waitForSync)

The optional waitForSync parameter can be used to force synchronization of the document deletion operation to disk even in case that the waitForSync flag had been disabled for the entire collection. Thus, the waitForSync parameter can be used to force synchronization of just specific operations. To use this, set the waitForSync parameter to true. If the waitForSync parameter is not specified or set to false, then the collection’s default waitForSync behavior is applied. The waitForSync parameter cannot be used to disable synchronization for collections that have a default waitForSync value of true.


collection.removeByExample(document, waitForSync, limit)

The optional limit parameter can be used to restrict the number of removals to the specified value. If limit is specified but less than the number of documents in the collection, it is undefined which documents are removed.

Examples

db.example.removeByExample( {Hello : "world"} );

collection.removeByKeys(keys)

Looks up the documents in the specified collection using the array of keys provided, and removes all documents from the collection whose keys are contained in the keys array. Keys for which no document can be found in the underlying collection are ignored, and no exception will be thrown for them.

The method will return an object containing the number of removed documents in the removed sub-attribute, and the number of not-removed/ignored documents in the ignored sub-attribute.

This method is deprecated in favor of the array variant of remove().

Examples

var keys = [ ];
for (var i = 0; i < 5; ++i) {
  db.example.insert({ _key: "test" + i, value: i });
  keys.push("test" + i);
}
db.example.removeByKeys(keys);
Show output

collection.replace(document, data [, options])

collection.replace(object, data)

Replaces an existing document described by the object, which must be an object containing the _id or _key attribute. There must be a document with that _id or _key in the current collection. This document is then replaced with the data given as second argument. Any attribute _id, _key or _rev in data is ignored.

The method returns a document with the attributes _id, _key, _rev and _oldRev. The attribute _id contains the document identifier of the updated document, the attribute _rev contains the document revision of the updated document, the attribute _oldRev contains the revision of the old (now replaced) document.

If the object contains a _rev attribute, the method first checks that the specified revision is the current revision of that document. If not, there is a conflict, and an error is thrown.


collection.replace(object, data, options)

Replaces an existing document, with additional options passed as an object:

  • waitForSync: One can force synchronization of the document creation operation to disk even in case that the waitForSync flag is been disabled for the entire collection. Thus, the waitForSync option can be used to force synchronization of just specific operations. To use this, set the waitForSync parameter to true. If the waitForSync parameter is not specified or set to false, then the collection’s default waitForSync behavior is applied. The waitForSync parameter cannot be used to disable synchronization for collections that have a default waitForSync value of true.
  • overwrite: If this flag is set to true, a _rev attribute in the object is ignored.
  • returnNew: If this flag is set to true, the complete new document is returned in the output under the attribute new.
  • returnOld: If this flag is set to true, the complete previous revision of the document is returned in the output under the attribute old.
  • silent: If this flag is set to true, no output is returned.

collection.replace(document-identifier, data [, options])

Replaces an existing document described by a document identifier, optionally with additional options passed as an object.

No revision check is performed.


collection.replace(document-key, data [, options])

Replaces an existing document described by a document key, optionally with additional options passed as an object.

No revision check is performed.


collection.replace(document-array, data-array [, options])

This variant allows you to perform the replace operation on two whole arrays of arguments. The two arrays given as document-array and data-array must have the same length. The behavior is exactly as if replace() would have been called on all respective members of the two arrays in pairs and all results are returned in an array. If an error occurs with any of the documents, no exception is raised! Instead of a document, an error object is returned in the result array.

Examples

Create and update a document:

a1 = db.example.insert({ a : 1 });
a2 = db.example.replace(a1, { a : 2 });
a3 = db.example.replace(a1, { a : 3 }); 
a3 = db.example.replace(a1, { a : 3 }, { overwrite: true });
Show output

Use a document identifier:

a1 = db.example.insert({ a : 1 });
a2 = db.example.replace("example/3903044", { a : 2 });
Show output

collection.replaceByExample(example, newValue [, waitForSync [, limit]])

Replaces all documents matching an example with a new document body. The entire document body of each document matching the example is replaced with newValue. The document meta-attributes _id, _key and _rev are not replaced.

The optional waitForSync parameter can be used to force synchronization of the document replacement operation to disk even in case that the waitForSync flag had been disabled for the entire collection. Thus, the waitForSync parameter can be used to force synchronization of just specific operations. To use this, set the waitForSync parameter to true. If the waitForSync parameter is not specified or set to false, then the collection’s default waitForSync behavior is applied. The waitForSync parameter cannot be used to disable synchronization for collections that have a default waitForSync value of true.

The optional limit parameter can be used to restrict the number of replacements to the specified value. If limit is specified but less than the number of documents in the collection, it is undefined which documents are replaced.

Examples

db.example.insert({ Hello : "world" });
db.example.replaceByExample({ Hello: "world" }, {Hello: "mars"}, false, 5);
Show output

collection.save(data [, options])

See collection.insert(data [, options]).

collection.toArray()

Converts the entire collection into an array of documents.

Avoid calling this method on a collection in production environments as it creates a copy of your collection data in memory, which may require a substantial amount of resources depending on the number and size of the documents in the collection.

collection.update(document, data [, options])

collection.update(object, data)

Updates an existing document described by the object, which must be an object containing the _id or _key attribute. There must be a document with that _id or _key in the current collection. This document is then patched with the data given as second argument. Any attribute _id, _key or _rev in data is ignored.

The method returns a document with the attributes _id, _key, _rev and _oldRev.

  • The _key and _id attributes contains the document key and document identifier of the updated document.
  • The _rev attribute contains the document revision of the updated document
  • The _oldRev attribute contains the revision of the old (now updated) document.

If the object contains a _rev attribute, the method first checks that the specified revision is the current revision of that document. If not, there is a conflict, and an error is raised.


collection.update(object, data, options)

Updates an existing document, with additional options passed as an object:

  • waitForSync: One can force synchronization of the document creation operation to disk even in case that the waitForSync flag is been disabled for the entire collection. Thus, the waitForSync option can be used to force synchronization of just specific operations. To use this, set the waitForSync parameter to true. If the waitForSync parameter is not specified or set to false, then the collection’s default waitForSync behavior is applied. The waitForSync parameter cannot be used to disable synchronization for collections that have a default waitForSync value of true.
  • overwrite: If this flag is set to true, a _rev attribute in the selector is ignored.
  • returnNew: If this flag is set to true, the complete new document is returned in the output under the attribute new.
  • returnOld: If this flag is set to true, the complete previous revision of the document is returned in the output under the attribute old.
  • silent: If this flag is set to true, no output is returned.
  • keepNull: The optional keepNull parameter can be used to modify the behavior when handling null values. Normally, null values are stored in the database. By setting the keepNull parameter to false, this behavior can be changed so that top-level attributes and sub-attributes in data with null values are removed from the target document (but not attributes of objects that are nested inside of arrays).
  • mergeObjects: Controls whether objects (not arrays) will be merged if present in both the existing and the patch document. If set to false, the value in the patch document will overwrite the existing document’s value. If set to true, objects will be merged. The default is true.

collection.update(document-identifier, data [, options])

Updates an existing document described by a document identifier, optionally with additional options passed as an object.

No revision check is performed.


collection.update(document-key, data [, options])

Updates an existing document described by a document key, optionally with additional options passed as an object.

No revision check is performed.


collection.update(document-array, data-array [, options])

This variant allows you to perform the operation on two whole arrays of arguments. The two arrays given as document-array and data-array must have the same length. The behavior is exactly as if update() would have been called on all respective members of the two arrays in pairs and all results are returned in an array. If an error occurs with any of the documents, no exception is raised! Instead of a document, an error object is returned in the result array.

Examples

Create and update a document:

a1 = db.example.insert({"a" : 1});
a2 = db.example.update(a1, {"b" : 2, "c" : 3});
a3 = db.example.update(a1, {"d" : 4}); 
a4 = db.example.update(a2, {"e" : 5, "f" : 6 });
db.example.document(a4);
a5 = db.example.update(a4, {"a" : 1, c : 9, e : 42 });
db.example.document(a5);
Show output

Use a document identifier:

a1 = db.example.insert({"a" : 1});
a2 = db.example.update("example/18612115", { "x" : 1, "y" : 2 });
Show output

Use the keepNull parameter to remove attributes with null values:

db.example.insert({"a" : 1});
db.example.update("example/19988371", { "b" : null, "c" : null, "d" : 3 });
db.example.document("example/19988371");
db.example.update("example/19988371", { "a" : null }, false, false);
db.example.document("example/19988371");
db.example.update("example/19988371", { "b" : null, "c": null, "d" : null }, false, false);
db.example.document("example/19988371");
Show output

Patching array values:

db.example.insert({
  "a" : { "one" : 1, "two" : 2, "three" : 3 },
  "b" : { }
});

db.example.update("example/20774803", {
  "a" : { "four" : 4 },
  "b" : { "b1" : 1 }
});

db.example.document("example/20774803");

db.example.update("example/20774803", {
  "a" : { "one" : null },
  "b" : null
}, false, false);

db.example.document("example/20774803");
Show output

collection.updateByExample(example, newValue [, options])

collection.updateByExample(example, newValue [, keepNull [, waitForSync [, limit]]])

Updates all documents matching an example with a new document body. Specific attributes in the document body of each document matching the example are updated with the values from newValue. The document meta-attributes _id, _key and _rev cannot be updated.

The optional keepNull parameter can be used to modify the behavior when handling null values. Normally, null values are stored in the database. By setting the keepNull parameter to false, this behavior can be changed so that top-level attributes and sub-attributes in data with null values are removed from the target document (but not attributes of objects that are nested inside of arrays).

The optional waitForSync parameter can be used to force synchronization of the document replacement operation to disk even in case that the waitForSync flag had been disabled for the entire collection. Thus, the waitForSync parameter can be used to force synchronization of just specific operations. To use this, set the waitForSync parameter to true. If the waitForSync parameter is not specified or set to false, then the collection’s default waitForSync behavior is applied. The waitForSync parameter cannot be used to disable synchronization for collections that have a default waitForSync value of true.

The optional limit parameter can be used to restrict the number of updates to the specified value. If limit is specified but less than the number of documents in the collection, it is undefined which documents are updated.


collection.updateByExample(document, newValue, options)

Using this variant, the options for the operation can be passed using an object with the following sub-attributes:

  • keepNull
  • waitForSync
  • limit
  • mergeObjects

Examples

db.example.insert({ Hello : "world", foo : "bar" });
db.example.updateByExample({ Hello: "world" }, { Hello: "foo", World: "bar" }, false);
db.example.byExample({ Hello: "foo" }).toArray()
Show output

Edge documents

edge-collection.edges(vertex)

Edges are normal documents that always contain a _from and a _to attribute. Therefore, you can use the document methods to operate on edges. The following methods, however, are specific to edges.

edge-collection.edges(vertex)

The edges() operator finds all edges starting from (outbound) or ending in (inbound) vertex.


edge-collection.edges(vertices)

The edges operator finds all edges starting from (outbound) or ending in (inbound) a document from vertices, which must be a list of documents or document identifiers.

var vcoll = db._create("vertex");
var ecoll = db._createEdgeCollection("relation");
var myGraph = {};
myGraph.v1 = db.vertex.insert({ name : "vertex 1" });
myGraph.v2 = db.vertex.insert({ name : "vertex 2" });
myGraph.e1 = db.relation.insert(myGraph.v1, myGraph.v2, { label : "knows"});
db._document(myGraph.e1);
db.relation.edges(myGraph.e1._id);
Show output

edge-collection.inEdges(vertex)

The inEdges() operator finds all edges ending in (inbound) vertex.


edge-collection.inEdges(vertices)

The inEdges() operator finds all edges ending in (inbound) a document from vertices, which must be a list of documents or document identifiers.

Examples

var vcoll = db._create("vertex");
var ecoll = db._createEdgeCollection("relation");
var myGraph = {};
myGraph.v1 = db.vertex.insert({ name : "vertex 1" });
myGraph.v2 = db.vertex.insert({ name : "vertex 2" });
myGraph.e1 = db.relation.insert(myGraph.v1, myGraph.v2, { label : "knows"});
db._document(myGraph.e1);
db.relation.inEdges(myGraph.v1._id);
db.relation.inEdges(myGraph.v2._id);
Show output

edge-collection.outEdges(vertex)

The outEdges() operator finds all edges starting from (outbound) vertices.


edge-collection.outEdges(vertices)

The outEdges() operator finds all edges starting from (outbound) a document from vertices, which must be a list of documents or document identifiers.

Examples

var vcoll = db._create("vertex");
var ecoll = db._createEdgeCollection("relation");
var myGraph = {};
myGraph.v1 = db.vertex.insert({ name : "vertex 1" });
myGraph.v2 = db.vertex.insert({ name : "vertex 2" });
myGraph.e1 = db.relation.insert(myGraph.v1, myGraph.v2, { label : "knows"});
db._document(myGraph.e1);
db.relation.outEdges(myGraph.v1._id);
db.relation.outEdges(myGraph.v2._id);
Show output