# Collections

## Creating Collections

This article describes how to create collections in Advanced Usergrid. All entities are automatically associated with a corresponding collection based on the type property of the entity. You may create empty collections if you wish, but creating an entity of a new type will automatically create a corresponding collection for you. For example, creating a new custom "item" entity, creates an "items" collection.

__Note__: Although not shown in the API examples below, you need to provide a valid access token with each API call. See [Authenticating users and application clients](../security-and-auth/authenticating-users-and-application-clients.html) for details.

### Creating a collection

The following example shows how to create an empty collection. Alternatively, you can create a collection simply by creating a new entity with a 'type' property that corresponds to the collection you wish to create. For more on creating entities, see Creating Custom Data Entities

### Request Syntax

    curl -X POST https://api.usergrid.com/<org>/<app>/<collection_name>

Parameters

Parameter	    Description
---------       -----------
org	            Organization UUID or organization name
app	            Application UUID or application name
collection name	Name of the collection to create. 

If the provided value is not a plural word, Usergrid will pluralize it. For example, providing 'item' will create a collection named 'items' but providing 'items' will not create 'itemses'.

### Example Request/Response

Request:

    curl -X POST "https://api.usergrid.com/your-org/your-app/item"

Response:

    {
      "action" : "post",
      "application" : "f34f4222-a166-11e2-a7f7-02e81adcf3d0",
      "params" : { },
      "path" : "/items",
      "uri" : "http://api.usergrid.com/your-org/your-app/items",
      "entities" : [ ],
      "timestamp" : 1378857079220,
      "duration" : 31,
      "organization" : "your-org",
      "applicationName" : "your-app"
    }
 
 
## Collection Settings

Usergrid allows you to specify settings for each of your Collections. 
Collections may have a *_settings* resource with the following URI pattern:

	/{org-identifier}/{app-identifier}/{collection-name}/_settings
	
If a Collection does not have a _settings resource,
then doing an HTTP GET on that URI will yield the normal Collection resource.
For example here a request and respinse for settings for the Collection "battles", which does not yet have _settigs:

	curl "https//api.usergrid.com/test-organization/settingstest/battles/_settings?access_token=YWM..."
	{
	  "action" : "get",
	  "application" : "7fd6c414-2cb6-11e6-8b07-0a669fe1d66e",
	  "params" : { },
	  "path" : "/battles",
	  "uri" : "https//api.usergrid.com/test-organization/settingstest/battles",
	  "entities" : [ ],
	  "timestamp" : 1465308535753,
	  "duration" : 175,
	  "organization" : "test-organization",
	  "applicationName" : "settingstest"
	}
	
Once a Collection has a _settings resource, here's what it might look like:
	
	curl "0:8080/test-organization/settingstest/battles/_settings?access_token=YWM..."
	{
	  "action" : "get",
	  "application" : "7fd6c414-2cb6-11e6-8b07-0a669fe1d66e",
	  "params" : { },
	  "path" : "/battles",
	  "uri" : "https//api.usergrid.com/test-organization/settingstest/battles",
	  "entities" : [ ],
	  "data" : {
	    "lastUpdated" : 1465311161543,
	    "lastReindexed" : 0,
	    "fields" : "all",
	    "region" : "us-east-1",
	    "lastUpdateBy" : "super@usergrid.com"
	  },
	  "timestamp" : 1465311177535,
	  "duration" : 6,
	  "organization" : "test-organization",
	  "applicationName" : "settingstest"
	}

	
Collection settings are useful for setting up Selective Indexing. Let's discuss that next.

  
## Setting up Selective Indexing via Collection Settings
 
Indexing is expensive and now it can be done selectively.

In the beginning, Usergrid indexed each and every field of an Entity. 
If a field was an object, the the fields of that object would also be indexed.
Indexing everything is very convenient because it means you can query on any field,
but indexing everything is expensive in terms of performance; 
it slows down Entity creation and update.
Indexing everything is also expensive in terms of storage, 
it takes up space and makes puts strain on the system.

Staring with Usegrid 2.1.1, you can specify a "schema" for each Collection.
You can tell Usergrid which fields should be indexed or 
you can tell Usergrid to completely skip indexing for a collection. 

### Specifying a Schema for a Collection

There are three ways to specify a schema for a Collection. 
You can specify that all fields are to be index, you can specify none or 
you can specify a list of the fields that should be indexed. 
You do this by POSTing or PUTing a _settings resource for the Collection with one field named "fields".

There are three possible values for "fields":

Fields Setting                 Type     Meaning
--------------                 ----     -------
"fields":"all"                 String   Index all Entity fields
"fields":"none"                String   Index no fields; completely skip indexing for this collection.
"fields":["field1", "field2"]  Array    Index all fields whose names are listed in the array value.


#### Example: Turn off Indexing for a Collection

This example shows how you would use curl to set the schema if you want to turn off indexing for a collection:

	curl -X PUT "0:8080/test-organization/settingstest/_settings?access_token=YWM..." -d '{"fields":"none"}'
	{
	  "action" : "put",
	  "application" : "7fd6c414-2cb6-11e6-8b07-0a669fe1d66e",
	  "params" : { },
	  "path" : "/_settings",
	  "uri" : "http://localhost:8080/test-organization/settingstest/_settings",
	  "entities" : [ {
	    "uuid" : "6fc783c6-2cc3-11e6-8fce-0a669fe1d66e",
	    "type" : "_setting",
	    "created" : 1465312858697,
	    "modified" : 1465312858697,
	    "fields" : "none",
	    "metadata" : {
	      "path" : "/_settings/6fc783c6-2cc3-11e6-8fce-0a669fe1d66e",
	      "size" : 347
	    }
	  } ],
	  "timestamp" : 1465312858688,
	  "duration" : 63,
	  "organization" : "test-organization",
	  "applicationName" : "settingstest"
	}


#### Example: Index only one field of a Collection

This example shows how you would use curl to set the schema if you only want the "year" field to be indexed:

	curl -X PUT "0:8080/test-organization/settingstest/_settings?access_token=YWM..." -d '{"fields":["year"]}'
	{
	  "action" : "put",
	  "application" : "7fd6c414-2cb6-11e6-8b07-0a669fe1d66e",
	  "params" : { },
	  "path" : "/_settings",
	  "uri" : "http://localhost:8080/test-organization/settingstest/_settings",
	  "entities" : [ {
	    "uuid" : "6fc783c6-2cc3-11e6-8fce-0a669fe1d66e",
	    "type" : "_setting",
	    "created" : 1465312858697,
	    "modified" : 1465312858697,
	    "fields" : [ "year" ],
	    "metadata" : {
	      "path" : "/_settings/6fc783c6-2cc3-11e6-8fce-0a669fe1d66e",
	      "size" : 347
	    }
	  } ],
	  "timestamp" : 1465312858688,
	  "duration" : 63,
	  "organization" : "test-organization",
	  "applicationName" : "settingstest"
	}


## Retrieving Collections

This article describes how to retrieve all of the entities in a collection.

<div class="admonition note"> <p class="first admonition-title">Note</p> <p class="last">
By default, the Usergrid API returns 10 entities per request. For collections with more than 10 entities, use the returned 'cursor' property to retrieve the next 10 entities in the result set. You may also use the LIMIT parameter in a query string to increase the number of results returned. For more information on using cursors, see [Query Parameters](../data-queries/query-parameters.html).</p></div>

__Note__: Although not shown in the API examples below, you need to provide a valid access token with each API call. See [Authenticating users and application clients](../security-and-auth/authenticating-users-and-application-clients.html) for details.

### Retrieving sets of entities from a collection

### Request Syntax

    curl -X GET https://api.usergrid.com/<org>/<app>/<collection>
    
Parameters

Parameter	Description
---------   -----------
org	        Organization UUID or organization name
app	        Application UUID or application name
collection	Collection UUID or collection name

### Example Request/Response

Request:

    curl -X GET "https://api.usergrid.com/your-org/your-app/items"

Response:

    {
          "action" : "get",
          "application" : "f34f4222-a166-11e2-a7f7-02e81adcf3d0",
          "params" : { },
          "path" : "/items",
          "uri" : "http://api.usergrid.com/your-org/your-app/items",
          "entities" : [ {
                "uuid" : "5bb76bca-1657-11e3-903f-9ff6c621a7a4",
                "type" : "item",
                "name" : "milk",
                "created" : 1378405020796,
                "modified" : 1378405020796,
                "metadata" : {
                      "path" : "/items/5bb76bca-1657-11e3-903f-9ff6c621a7a4"
                },
                "name" : "milk",
                "price" : "3.25"
          }, {
            "uuid" : "1a9356ba-1682-11e3-a72a-81581bbaf055",
            "type" : "item",
            "name" : "bread",
            "created" : 1378423379867,
            "modified" : 1378423379867,
            "metadata" : {
                  "path" : "/items/1a9356ba-1682-11e3-a72a-81581bbaf055"
            },
            "name" : "bread",
            "price" : "2.50"
          } ],
          "timestamp" : 1378426821261,
          "duration" : 35,
          "organization" : "your-org",
          "applicationName" : "your-app",
          "count" : 2
    }   
    
## Updating Collections

This article describes how to perform batch updates on all entities in a collection. Batch updates require the use of a query string in the request, which can either specify all entities in the collection or a subset of entities for the update to be performed on. For more information on queries, see Querying your data.

__Note__: Although not shown in the API examples below, you need to provide a valid access token with each API call. See [Authenticating users and application clients](../security-and-auth/authenticating-users-and-application-clients.html) for details.

### Batch updating entities in a collection

### Request Syntax

    curl -X PUT https://api.usergrid.com/<org>/<app>/<collection>/?ql= -d {<property>}

Note the empty query string (ql=) appended to the URL.

Parameters

Parameter	Description
---------   -----------
org	        Organization UUID or organization name
app	        Application UUID or application name
collection	Collection UUID or collection name property	

An entity property to be updated, formatted as a key-value pair. For example:

    {"property_1":"value_1", "property_2":"value_2",...}

### Example Request/Response

Request:

    curl -X PUT https://api.usergrid.com/your-org/your-app/items/?ql= -d '{"availability":"in-stock"}'

Note the empty ?ql= query string.

Response:

    {
      "action" : "put",
      "application" : "f34f4222-a166-11e2-a7f7-02e81adcf3d0",
      "params" : {
        "ql" : [ "" ]
      },
      "path" : "/items",
      "uri" : "http://api.usergrid.com/your-org/your-app/items",
      "entities" : [ {
        "uuid" : "31847b9a-1a62-11e3-be04-8d05e96f700d",
        "type" : "item",
        "name" : "milk",
        "price" : "3.25",
        "availability" : "in-stock"
        "created" : 1378849479113,
        "modified" : 1378849567301,
        "name" : "milk",
      }, {
        "uuid" : "3192ac6a-1a62-11e3-a24f-496ca1d42ce7",
        "type" : "item",
        "name" : "bread",
        "price" : "4.00",
        "availability" : "in-stock"
        "created" : 1378849479206,
        "modified" : 1378849567351,
        "name" : "bread",
      } ],
      "timestamp" : 1378849567280,
      "duration" : 207,
      "organization" : "your-org",
      "applicationName" : "your-app"
    }
    
   
## Deleting Collections
This article describes how to batch delete entities in a collection. Batch deletes require the use of a query string in the request, which specifies a subset of entities to be deleted. For more information on queries, see Querying your data.

Currently, collections cannot be deleted; however, you can delete all of the entities from a collection.

__Note__: Although not shown in the API examples below, you need to provide a valid access token with each API call. See [Authenticating users and application clients](../security-and-auth/authenticating-users-and-application-clients.html) for details.

### Batch deleting entities in a collection

### Request Syntax

    curl -X DELETE https://api.usergrid.com/<org>/<app>/<collection>/?ql=<query>
    
Parameters

Parameter	Description
---------   -----------
org	        Organization UUID or organization name
app	        Application UUID or application name
collection	Collection UUID or collection name
query	    A query string that specifies the subset of entities to delete 

(for more information on queries, see Querying your data)

### Example Request/Response

The following example will delete the first 5 entities in a collection.

Request:

    curl -X DELETE https://api.usergrid.com/your-org/your-app/items/?ql="limit=5"
    
Response:

    {
      "action" : "delete",
      "application" : "f34f4222-a166-11e2-a7f7-02e81adcf3d0",
      "params" : {
        "ql" : [ "" ]
      },
      "path" : "/items",
      "uri" : "http://api.usergrid.com/your-org/your-app/items",
      "entities" : [ {
        "uuid" : "53fe3700-0abe-11e3-b1f7-1bd100b8059e",
        "type" : "item",
        "name" : "milk",
        "price" : "3.25",
        "created" : 1377129832047,
        "modified" : 1377129832047,
        "metadata" : {
          "path" : "/items/53fe3700-0abe-11e3-b1f7-1bd100b8059e"
        },
        "name" : "milk"
      }, {
        "uuid" : "5ae1fa7a-0abe-11e3-89ab-6be0003c809b",
        "type" : "item",
        "name" : "bread",
        "price" : "4.00",
        "created" : 1377129843607,
        "modified" : 1377129843607,
        "metadata" : {
          "path" : "/items/5ae1fa7a-0abe-11e3-89ab-6be0003c809b"
        },
        "name" : "bread"
      } ],
      "timestamp" : 1378848117272,
      "duration" : 12275,
      "organization" : "your-org",
      "applicationName" : "your-app"
    }