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Creating and Deleting Collections

Create collection

creates a collection

POST /_api/collection

Accessing collections by their numeric ID is deprecated from version 3.4.0 on. You should reference them via their names instead.

Query Parameters

  • waitForSyncReplication (optional): Default is 1 which means the server will only report success back to the client if all replicas have created the collection. Set to 0 if you want faster server responses and don’t care about full replication.

  • enforceReplicationFactor (optional): Default is 1 which means the server will check if there are enough replicas available at creation time and bail out otherwise. Set to 0 to disable this extra check.

A JSON object with these properties is required:

  • name: The name of the collection.

  • waitForSync: If true then the data is synchronized to disk before returning from a document create, update, replace or removal operation. (default: false)

  • doCompact: whether or not the collection will be compacted (default is true) This option is meaningful for the MMFiles storage engine only.

  • journalSize: The maximal size of a journal or datafile in bytes. The value must be at least 1048576 (1 MiB). (The default is a configuration parameter) This option is meaningful for the MMFiles storage engine only.

  • isSystem: If true, create a system collection. In this case 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 will do. (The default is false)

  • isVolatile: If true then the collection data is kept in-memory only and not made persistent. Unloading the collection will cause the collection data to be discarded. Stopping or re-starting the server will also cause full loss of data in the collection. Setting this option will make the resulting collection be slightly faster than regular collections because ArangoDB does not enforce any synchronization to disk and does not calculate any CRC checksums for datafiles (as there are no datafiles). This option should therefore be used for cache-type collections only, and not for data that cannot be re-created otherwise. (The default is false) This option is meaningful for the MMFiles storage engine only.

  • keyOptions: additional options for key generation. If specified, then keyOptions should be a JSON array containing the following attributes:

    • type: specifies the type of the key generator. The currently available generators are traditional, autoincrement, uuid and padded.

    The traditional key generator generates numerical keys in ascending order. The autoincrement key generator generates numerical keys in ascending order, the inital offset and the spacing can be configured The padded key generator generates keys of a fixed length (16 bytes) in ascending lexicographical sort order. This is ideal for usage with the RocksDB engine, which will slightly benefit keys that are inserted in lexicographically ascending order. The key generator can be used in a single-server or cluster. 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.

    • allowUserKeys: if set to true, then it is allowed to supply own key values in the _key attribute of a document. If set to false, then the key generator will solely be responsible for generating keys and supplying own key values in the _key attribute of documents is considered an error.

    • increment: increment value for autoincrement key generator. Not used for other key generator types.

    • offset: Initial offset value for autoincrement key generator. Not used for other key generator types.

  • type: (The default is 2): the type of the collection to create. The following values for type are valid:

  • 2: document collection

  • 3: edge collection

    • indexBuckets: The number of buckets into which indexes using a hash table are split. The default is 16 and this number has to be a power of 2 and less than or equal to 1024.

For very large collections one should increase this to avoid long pauses when the hash table has to be initially built or resized, since buckets are resized individually and can be initially built in parallel. For example, 64 might be a sensible value for a collection with 100 000 000 documents. Currently, only the edge index respects this value, but other index types might follow in future ArangoDB versions. Changes (see below) are applied when the collection is loaded the next time. This option is meaningful for the MMFiles storage engine only.

  • numberOfShards: (The default is 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: (The default is [ “_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 of 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: Values of shard key attributes cannot be changed once set. This option is meaningless in a single server setup.

  • replicationFactor: (The default is 1): in a cluster, this attribute determines how many copies of each shard are kept on different DBServers. 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 DBServers. Replication between them is synchronous, that is, every write operation to the “leader” copy will be 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.

  • distributeShardsLike: (The default is ”“): in an Enterprise Edition cluster, this attribute binds the specifics of sharding for the newly created collection to follow that of a specified existing collection. Note: Using this parameter has consequences for the prototype collection. It can no longer be dropped, before the sharding-imitating collections are dropped. Equally, backups and restores of imitating collections alone will generate warnings (which can be overridden) about missing sharding prototype.

  • shardingStrategy: This attribute specifies the name of the sharding strategy to use for the collection. Since ArangoDB 3.4 there are different sharding strategies to select from when creating a new collection. The selected shardingStrategy value will remain 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

If no sharding strategy is specified, the default will be hash for all collections, and enterprise-hash-smart-edge for all smart edge collections (requires 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.

  • smartJoinAttribute: In an Enterprise Edition cluster, this attribute determines an attribute of the collection that must contain the shard key value of the referred-to smart join collection. Additionally, the shard 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.

Creates a new collection with a given name. The request must contain an object with the following attributes.

Return codes

  • 400: If the collection-name is missing, then a HTTP 400 is returned.

  • 404: If the collection-name is unknown, then a HTTP 404 is returned.

Examples

shell> curl -X POST --header 'accept: application/json' --data-binary @- --dump - http://localhost:8529/_api/collection <<EOF
{ 
  "name" : "testCollectionBasics" 
}
EOF

HTTP/1.1 OK
content-type: application/json; charset=utf-8
x-content-type-options: nosniff

shell> curl -X POST --header 'accept: application/json' --data-binary @- --dump - http://localhost:8529/_api/collection <<EOF
{ 
  "name" : "testCollectionEdges", 
  "type" : 3 
}
EOF

HTTP/1.1 OK
content-type: application/json; charset=utf-8
x-content-type-options: nosniff
Show response body
shell> curl -X POST --header 'accept: application/json' --data-binary @- --dump - http://localhost:8529/_api/collection <<EOF
{ 
  "name" : "testCollectionUsers", 
  "keyOptions" : { 
    "type" : "autoincrement", 
    "increment" : 5, 
    "allowUserKeys" : true 
  } 
}
EOF

HTTP/1.1 OK
content-type: application/json; charset=utf-8
x-content-type-options: nosniff
Show response body

Drops a collection

drops a collection

DELETE /_api/collection/{collection-name}

Accessing collections by their numeric ID is deprecated from version 3.4.0 on. You should reference them via their names instead.

Path Parameters

  • collection-name (required): The name of the collection to drop.

Query Parameters

  • isSystem (optional): Whether or not the collection to drop is a system collection. This parameter must be set to true in order to drop a system collection.

Drops the collection identified by collection-name.

If the collection was successfully dropped, an object is returned with the following attributes:

  • error: false

  • id: The identifier of the dropped collection.

Return codes

  • 400: If the collection-name is missing, then a HTTP 400 is returned.

  • 404: If the collection-name is unknown, then a HTTP 404 is returned.

Examples

Using an identifier:

shell> curl -X DELETE --header 'accept: application/json' --dump - http://localhost:8529/_api/collection/68488

HTTP/1.1 OK
content-type: application/json; charset=utf-8
x-content-type-options: nosniff
Show response body

Using a name:

shell> curl -X DELETE --header 'accept: application/json' --dump - http://localhost:8529/_api/collection/products1

HTTP/1.1 OK
content-type: application/json; charset=utf-8
x-content-type-options: nosniff
Show response body

Dropping a system collection

shell> curl -X DELETE --header 'accept: application/json' --dump - http://localhost:8529/_api/collection/_example?isSystem=true

HTTP/1.1 OK
content-type: application/json; charset=utf-8
x-content-type-options: nosniff
Show response body

Truncate collection

truncates a collection

PUT /_api/collection/{collection-name}/truncate

Accessing collections by their numeric ID is deprecated from version 3.4.0 on. You should reference them via their names instead.

Path Parameters

  • collection-name (required): The name of the collection.

Removes all documents from the collection, but leaves the indexes intact.

Return codes

  • 400: If the collection-name is missing, then a HTTP 400 is returned.

  • 404: If the collection-name is unknown, then a HTTP 404 is returned.

Examples

shell> curl -X PUT --header 'accept: application/json' --dump - http://localhost:8529/_api/collection/products/truncate

HTTP/1.1 OK
content-type: application/json; charset=utf-8
location: /_api/collection/products/truncate
x-content-type-options: nosniff
Show response body
❮  Collections

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