The db object of the JavaScript API

The database object represents the currently selected database and provides access to information and methods for executing operations in the context of this database

The db object of the JavaScript API is available in arangosh by default, and can also be imported and used in Foxx services and other server-side JavaScript contexts from the @arangodb module.

Property access

  • db.<collection-name> and db["<collection-name>"] return a collection object for the specified collection if it exists.

  • db.<view-name> and db["<view-name>"] return a view object for the specified View if it exists.

Databases

db._createDatabase(name [, options [, users]])

Creates a new database with the specified name. There are restrictions for database names (see Database names).

You can only create new databases from within the _system database.

Note that even if the database is created successfully, there will be no change into the current database to the new database. Changing the current database must explicitly be requested by using the db._useDatabase() method.

The options attribute can be used to set defaults for collections that will be created in the new database (cluster only):

  • sharding: The sharding method to use. Valid values are: "" or "single". Setting this option to "single" will enable the OneShard feature in the Enterprise Edition.
  • replicationFactor: Default replication factor. Special values include "satellite", which will replicate the collection to every DB-Server, and 1, which disables replication.
  • writeConcern: 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 will refuse to write. The value of writeConcern cannot be greater than replicationFactor.

The optional users attribute can be used to create initial users for the new database. If specified, it must be a list of user objects. Each user object can contain the following attributes:

  • username: the user name as a string. This attribute is mandatory.
  • passwd: the user password as a string. If not specified, then it defaults to an empty string.
  • active: a boolean flag indicating whether the user account should be active or not. The default value is true.
  • extra: an optional JSON object with extra user information. The data contained in extra will be stored for the user but not be interpreted further by ArangoDB.

If no initial users are specified, a default user root will be created with an empty string password. This ensures that the new database will be accessible via HTTP after it is created.

You can create users in a database if no initial user is specified. Switch into the new database (username and password must be identical to the current session) and add or modify users with the following commands.

require("@arangodb/users").save(username, password, true);
require("@arangodb/users").update(username, password, true);
require("@arangodb/users").remove(username);

Alternatively, you can specify user data directly. For example:

db._createDatabase("newDB", {}, [{ username: "newUser", passwd: "123456", active: true}])

db._useDatabase(name)

Changes the current database to the specified database. Note that the database specified by name must already exist.

Changing the database might be disallowed in some contexts, for example, in server-side actions (including Foxx).

When performing this command from arangosh, the current credentials (username and password) will be re-used. These credentials might not be valid to connect to the database specified by name. Additionally, the database only be accessed from certain endpoints only. In this case, switching the database might not work, and the connection / session should be closed and restarted with different username and password credentials and/or endpoint data.

db._databases()

Returns the list of all existing databases.

The databases can only be listed from within the _system database.

db._dropDatabase(name)

Drops the specified database. The database specified by name must exist.

Databases can only be dropped from within the _system database. The _system database itself cannot be dropped.

Databases are dropped asynchronously, and will be physically removed if all clients have disconnected and references have been garbage-collected.

db._name()

Returns the name of the current database as a string.

Examples

require("@arangodb").db._name();
Show output

db._id()

Returns the identifier of the current database as a string.

Examples

require("@arangodb").db._id();
Show output

db._isSystem()

Returns whether the currently used database is the _system database.

The system database has some special privileges and properties, for example, database management operations such as creating or dropping databases can only be executed from within the _system database. The _system database itself cannot be dropped.

db._path()

Returns the filesystem path of the current database as a string.

This is a legacy method and always returns the string none with the RocksDB storage engine.

Examples

require("@arangodb").db._path();
Show output

db._properties()

Returns the properties of the current database as an object with the following attributes:

  • id: the database identifier
  • name: the database name
  • isSystem: the database type
  • path: the path to the database files (not used anymore, always "")
  • sharding: the sharding method to use for new collections (cluster only)
  • replicationFactor: default replication factor for new collections (cluster only)
  • writeConcern: a shard will refuse to write if less than this amount of copies are in sync (cluster only)

Examples

require("@arangodb").db._properties();
Show output

Collections

db._create(collection-name [, properties [, type] [, options]])

Create a new document collection or edge collection.

db._create(collection-name)

Creates a new document collection named collection-name with the default settings and returns a collection object.

If a collection or View with this name exists already, or if the name format is invalid, an error is thrown. For information about the naming constraints for collections, see Collection names.

db._create(collection-name, properties)

properties must be an object with the following attributes:

  • waitForSync (boolean, optional, default false): If true, creating, changing, or removing a document waits until the data is synchronized to disk.

  • keyOptions (object, optional): The options for key generation. If specified, then keyOptions should be an object containing the following attributes:

    • type (string): specifies the type of the key generator. The available generators are "traditional" (default), "autoincrement", "uuid" and "padded".

      • The traditional key generator generates numerical keys in ascending order. The sequence of keys is not guaranteed to be gap-free.
      • The autoincrement key generator generates numerical keys in ascending order, the initial offset and the spacing can be configured (note: autoincrement is only supported for non-sharded or single-sharded collections). The sequence of generated keys is not guaranteed to be gap-free, because a new key is generated on every document insert attempt, not just for successful inserts.
      • The padded key generator generates keys of a fixed length (16 bytes) in ascending lexicographical sort order. This is ideal for the RocksDB storage engine, which slightly benefits keys that are inserted in lexicographically ascending order. The key generator can be used in a single-server or cluster. The sequence of generated keys is not guaranteed to be gap-free.
      • The uuid key generator generates universally unique 128 bit keys, which are stored in hexadecimal human-readable format. This key generator can be used in a single-server or cluster to generate “seemingly random” keys. The keys produced by this key generator are not lexicographically sorted.

      Please note that keys are only guaranteed to be truly ascending in single server deployments and for collections that only have a single shard (that includes collections in a OneShard database). The reason is that for collections with more than a single shard, document keys are generated on Coordinator(s). For collections with a single shard, the document keys are generated on the leader DB-Server, which has full control over the key sequence.

    • allowUserKeys (boolean, optional): 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: The increment value for the autoincrement key generator. Not used for other key generator types.

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

  • schema (object|null, optional, default: 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, optional, default: null): An array of objects, each representing a Computed Value.

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

  • isSystem (boolean, optional, default: false): If true, create a system collection. In this case, the collection name should start with an underscore. End-users should normally create non-system collections only. API implementors may be required to create system collections in very special occasions, but normally a regular collection is sufficient.

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

  • numberOfShards (number, optional, default 1): In a cluster, this value determines the number of shards to create for the collection. In a single server setup, this option is meaningless.

  • shardKeys (array, optional, default: ["_key"]): In a cluster, this attribute determines which document attributes are used to determine the target shard for documents. Documents are sent to shards based on the values they have in their shard key attributes. The values of all shard key attributes in a document are hashed, and the hash value is used to determine the target shard. Note that values of shard key attributes cannot be changed once set. This option is meaningless in a single server setup.

    When choosing the shard keys, you must be aware of the following rules and limitations: In a sharded collection with more than one shard it is not possible to set up a unique constraint on an attribute that is not the one and only shard key given in shardKeys. This is because enforcing a unique constraint would otherwise make a global index necessary or need extensive communication for every single write operation. Furthermore, if _key is not the one and only shard key, then it is not possible to set the _key attribute when inserting a document, provided the collection has more than one shard. Again, this is because the database has to enforce the unique constraint on the _key attribute and this can only be done efficiently if this is the only shard key by delegating to the individual shards.

  • replicationFactor (number|string, optional, default 1): In a cluster, this attribute determines how many copies of each shard are kept on different DB-Servers. The value 1 means that only one copy (no synchronous replication) is kept. A value of k means that k-1 replicas are kept. Any two copies reside on different DB-Servers. Replication between them is synchronous, that is, every write operation to the “leader” copy is replicated to all “follower” replicas, before the write operation is reported successful.

    If a server fails, this is detected automatically and one of the servers holding copies take over, usually without an error being reported.

    When using the Enterprise Edition of ArangoDB the replicationFactor may be set to “satellite” making the collection locally joinable on every DB-Server. This reduces the number of network hops dramatically when using joins in AQL at the costs of reduced write performance on these collections.

  • writeConcern (number, optional, default 1): In a cluster, this attribute 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. The value of writeConcern cannot be greater than replicationFactor. Please note: during server failures this might lead to writes not being possible until the failover is sorted out and might cause write slow downs in trade for data durability.

  • shardingStrategy (optional): specifies the name of the sharding strategy to use for the collection. There are different sharding strategies to select from when creating a new collection. The selected shardingStrategy value remains fixed for the collection and cannot be changed afterwards. This is important to make the collection keep its sharding settings and always find documents already distributed to shards using the same initial sharding algorithm.

    The available sharding strategies are:

    • "community-compat": default sharding used by ArangoDB Community Edition before version 3.4
    • "enterprise-compat": default sharding used by ArangoDB Enterprise Edition before version 3.4
    • "enterprise-smart-edge-compat": default sharding used by smart edge collections in ArangoDB Enterprise Edition before version 3.4
    • "hash": default sharding used for new collections starting from version 3.4 (excluding smart edge collections)
    • "enterprise-hash-smart-edge": default sharding used for new smart edge collections starting from version 3.4
    • enterprise-hex-smart-vertex: sharding used for vertex collections of EnterpriseGraphs

    If no sharding strategy is specified, the default is hash for all normal collections, enterprise-hash-smart-edge for all smart edge collections, and enterprise-hex-smart-vertex for EnterpriseGraph vertex collections (the latter two require the Enterprise Edition of ArangoDB). Manually overriding the sharding strategy does not yet provide a benefit, but it may later in case other sharding strategies are added.

    In single-server mode, the shardingStrategy attribute is meaningless and is ignored.

  • distributeShardsLike (string, optional, default: ""): The name of another collection. If this property is set in a cluster, the collection copies the replicationFactor, numberOfShards, shardingStrategy, and writeConcern properties from the specified collection (referred to as the prototype collection) and distributes the shards of this collection in the same way as the shards of the other collection. In an Enterprise Edition cluster, this data co-location is utilized to optimize queries.

    You need to use the same number of shardKeys as the prototype collection, but you can use different attributes.

    Using this parameter has consequences for the prototype collection. It can no longer be dropped unless the sharding-imitating collections are dropped beforehand. Equally, backups and restores of imitating collections alone result in errors about missing sharding prototypes.

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

  • isDisjoint (boolean): Whether the collection is for a Disjoint SmartGraph (Enterprise Edition only). This is an internal property.

  • smartGraphAttribute (string, optional): 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, optional): 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. Additionally, the sharding key for a document in this collection must contain the value of this attribute, followed by a colon, followed by the actual primary key of the document.

    This feature can only be used in the Enterprise Edition and requires the distributeShardsLike attribute of the collection to be set to the name of another collection. It also requires the shardKeys attribute of the collection to be set to a single shard key attribute, with an additional : at the end. A further restriction is that whenever documents are stored or updated in the collection, the value stored in the smartJoinAttribute must be a string.

db._create(collection-name, properties, type)

Specifies the optional type of the collection, it can either be document or edge. On default it is document. Instead of giving a type you can also use db._createEdgeCollection() or db._createDocumentCollection().

db._create(collection-name, properties [, type], options)

As an optional third parameter (if the type string is omitted) or as fourth parameter, you can specify an optional options map that controls how the cluster creates the collection. These options are only relevant at creation time and are not persisted:

  • waitForSyncReplication (default: true) If enabled, the server only reports success back to the client if all replicas have created the collection. Set to false if you want faster server responses and don’t care about full replication.

  • enforceReplicationFactor (default: true) If enabled, the server checks if there are enough replicas available at creation time and bails out otherwise. Set to false to disable this extra check.

Examples

With defaults:

var coll = db._create("users");
coll.properties();
Show output

With properties:

var coll = db._create("users", { waitForSync: true });
coll.properties();
Show output

With a key generator:

var coll = db._create("users", { keyOptions: { type: "autoincrement", offset: 10, increment: 5 } });
db.users.save({ name: "user 1" });
db.users.save({ name: "user 2" });
db.users.save({ name: "user 3" });
Show output

With a special key option:

var coll = db._create("users", { keyOptions: { allowUserKeys: false } });
db.users.save({ name: "user 1" });
db.users.save({ name: "user 2", _key: "myuser" }); 
db.users.save({ name: "user 3" });
Show output

db._createDocumentCollection(collection-name [, properties])

See db._create(collection-name [, properties]).

db._createEdgeCollection(collection-name [, properties])

db._createEdgeCollection(collection-name)

Creates a new edge collection named collection-name with the default settings and returns a collection object.

If a collection or View with this name exists already, an error is thrown.

db._createEdgeCollection(collection-name, properties)

Creates a new edge collection with the specified properties. See db._create(collection-name, properties) for the available properties.

db._collections()

Returns all collections of the current database. Each array element is a collection object.

Examples

db._collections();
Show output

db._collection(collection)

db._collection(collection-name)

Returns the collection with the specified name as a collection object, or null if no such collection exists.

db._collection(collection-identifier)

Returns the collection with the given identifier as a collection object, or null if no such collection exists.

Accessing collections by identifier is discouraged for end-users. Access collections using the collection name instead.

Examples

Get a collection by name:

db._collection("demo");
Show output

Get a collection by identifier:

arangosh> db._collection(123456);
[ArangoCollection 123456, "demo" (type document, status loaded)]

Unknown collection:

db._collection("unknown");
Show output

db._truncate(collection)

Truncates a collection, removing all documents but keeping all its index definitions and other settings.

db._truncate(collection-name)

Truncates a collection named collection-name. No error is thrown if there is no such collection.

db._truncate(collection-identifier)

Truncates a collection identified by collection-identified. No error is thrown if there is no such collection.

Examples

Truncates a collection:

var coll = db._collection("example");
var doc = coll.save({ "Hello" : "World" });
coll.count();
db._truncate(coll);
coll.count();
Show output

Truncates a collection identified by name:

var coll = db._collection("example");
var doc = coll.save({ "Hello" : "World" });
coll.count();
db._truncate("example");
coll.count();
Show output

db._drop(collection [, options])

Drops a collection and all its indexes and data.

db._drop(collection-name)

Drops a collection named collection-name and all its indexes. No error is thrown if there is no such collection.

db._drop(collection-identifier)

Drops a collection identified by collection-identifier with all its indexes and data. No error is thrown if there is no such collection.

db._drop(collection-name, options)

In order to drop a system collection, you must specify an options object with attribute isSystem set to true. Otherwise, it is not possible to drop system collections.

Collections in a cluster deployment that are prototypes for collections with distributeShardsLike parameter cannot be dropped.

Examples

Drops a collection:

var coll = db._collection("example");
db._drop(coll);
Show output

Drops a collection identified by name:

coll = db._collection("example");
db._drop("example");
coll;
Show output

Drops a system collection

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

Documents

db._exists(document)

db._exists(object)

Checks whether a document exists using an object containing an _id attribute.

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

Instead of returning the found document or an error, this method only returns 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 identifier, or an object with an invalid or missing _id attribute.

db._exists(document-identifier)

Checks whether a document exists using a document identifier.

db._update(document, data [, options])

db._update(object, data)

Updates an existing document described by the object, which must be an object containing the _id attribute. There must be a document with that _id in the current database. 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 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 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 thrown.

db._update(object, data, options)

Updates an existing document with additional boolean options passed via 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.

db._update(document-identifier, data)

db._update(document-identifier, data, options)

Updates an existing document described by a document identifier, optionally with additional boolean options (see above).

No revision check is performed.

Examples

Create and update a document:

a1 = db.example.insert({ a : 1 });
a2 = db._update(a1, { b : 2 });
a3 = db._update(a1, { c : 3 });
Show output

Ignore a revision mismatch when updating the document:

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

db._replace(document, data)

db._replace(object, data)

Replaces an existing document described by the object, which must be an object containing the _id attribute. There must be a document with that _id in the current database. 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 boolean options passed via 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.

db._replace(document-identifier, data)

db._replace(document-identifier, data, options)

Replaces an existing document described by a document identifier, optionally with boolean options (see above).

No revision check is performed.

Examples

Create and replace a document:

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

Ignore a revision mismatch when replacing the document:

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

db._remove(document)

db._remove(object)

Removes a document described by the object, which must be an object containing the _id attribute. There must be a document with that _id in the current database. 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.

db._remove(object, options)

Removes a document, with additional boolean options passed via 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.
  • 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.

db._remove(document-identifier)

db._remove(document-identifier, options)

Removes an existing document described by a document identifier, optionally with additional boolean options (see above).

No revision check is performed.

Examples

Remove a document:

a1 = db.example.insert({ a : 1 });
db._remove(a1);
db._remove(a1); 
db._remove(a1, {overwrite: true});
Show output

Remove the document in the revision a1 with a conflict:

a1 = db.example.insert({ a : 1 });
a2 = db._replace(a1, { a : 2 });
db._remove(a1); 
db._remove(a1, {overwrite: true});
db._document(a1);
Show output

Remove a document using a document identifier:

db.example.insert({ _key: "123456", a: 1 } );
db.example.remove("example/123456");
Show output

Views

db._createView(name, type [, properties])

Creates a new View and returns a view object.

name is a string and the name of the View. No View or collection with the same name may already exist in the current database. For information about the naming constraints for Views, see View names.

type must be the string "arangosearch", as it is currently the only supported View type.

properties is an optional object containing View configuration specific to each View-type.

Examples

var view = db._createView("example", "arangosearch");
view.properties()
db._dropView("example")
Show output

db._views()

Returns all Views of the current database.

Each element of the returned array is a view object.

Examples

List all Views:

db._views();
Show output

db._view(view)

db._view(view-name)

Returns the View with the given name as a view object, or null if no such View exists.

var view = db._view("example");
// or, alternatively
var view = db["example"];
Show output

db._view(view-identifier)

Returns the View with the given identifier as a view object, or null if no such View exists.

Accessing Views by identifier is discouraged for end-users. Access Views using the View name instead.

Examples

Get a View by name:

db._view("demoView");
Show output

Unknown View:

db._view("unknown");
Show output

db._dropView(view)

db._dropView(name)

Drops a view named name and all its data.

No error is thrown if there is no such View.

db._dropView(view-identifier)

Drops a View identified by view-identifier with all its data. No error is thrown if there is no such View.

Examples

Drop a view:

var view = db._createView("exampleView", "arangosearch");
db._dropView("exampleView");
db._view("exampleView");
Show output

AQL

db._createStatement(queryString)

See db._createStatement().

db._query(queryString [, bindVars [, mainOptions] [, subOptions]])

See db._query().

db._explain(queryString)

See db._explain().

db._parse(queryString)

See db._parse().

Indexes

db._index(index)

Fetches an index by identifier.

See db._index().

db._dropIndex(index)

Drops an index by identifier.

See db._dropIndex().

Transactions

db._createTransaction()

Starts a Stream Transaction.

See db._createTransaction().

db._executeTransaction()

Executes a JavaScript Transaction.

See db._executeTransaction().

Global

db._compact(options)

Compacts the entire data, for all databases.

This command can be used to reclaim disk space after substantial data deletions have taken place. It requires superuser access.

The optional options attribute can be used to get more control over the compaction. The following attributes can be used in it:

  • changeLevel: whether or not compacted data should be moved to the minimum possible level. The default value is false.
  • compactBottomMostLevel: whether or not to compact the bottommost level of data. The default value is false.
This command can cause a full rewrite of all data in all databases, which may take very long for large databases. It should thus only be used with care and only when additional I/O load can be tolerated for a prolonged time.

db._engine()

Returns the name of the storage engine used by the server (rocksdb), as well as a list of supported features such as types of indexes.

db._engineStats()

Returns statistics related to the storage engine activity, including figures about data size, cache usage, etc.

db._version()

Returns the server version string.

Note that this is different to the version of the database.

Examples

require("@arangodb").db._version();
Show output

License

db._getLicense()

Returns the current license.

See db._getLicense().

db._setLicense(data)

Sets a license.

See db._setLicense(data).

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