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Version: 20 R6 BETA

$method

This parameter allows you to define the operation to execute with the returned entity or entity selection.

Available syntaxes

SyntaxExampleDescription
$method=deletePOST /Employee?$filter="ID=11"& $method=deleteDeletes the current entity, entity collection, or entity selection
$method=entitysetGET /People/?$filter="ID>320"& $method=entityset& $timeout=600Creates an entity set in 4D Server's cache based on the collection of entities defined in the REST request
$method=releaseGET /Employee/$entityset/<entitySetID>?$method=releaseReleases an existing entity set stored in 4D Server's cache
$method=subentitysetGET /Company(1)/staff?$expand=staff& $method=subentityset& $subOrderby=lastName ASCCreates an entity set based on the collection of related entities defined in the REST request
$method=updatePOST /Person/?$method=updateUpdates and/or creates one or more entities

$method=delete

Deletes the current entity, entity collection, or entity selection (created through REST)

Description

With $method=delete, you can delete an entity or an entire entity collection. You can define the collection of entities by using, for example, $filter or specifying one directly using \{dataClass\}({key}) (e.g., /Employee(22)).

You can also delete the entities in an entity set, by calling $entityset/\{entitySetID\}.

Example

You can then write the following REST request to delete the entity whose key is 22:

POST /rest/Employee(22)/?$method=delete

You can also do a query as well using $filter:

POST /rest/Employee?$filter="ID=11"&$method=delete

You can also delete an entity set using $entityset/{entitySetID}:

POST /rest/Employee/$entityset/73F46BE3A0734EAA9A33CA8B14433570?$method=delete

Response:

{
"ok": true
}

$method=entityset

Creates an entity set in 4D Server's cache based on the collection of entities defined in the REST request

Description

When you create a collection of entities in REST, you can also create an entity set that will be saved in 4D Server's cache. The entity set will have a reference number that you can pass to $entityset/\{entitySetID\} to access it. By default, it is valid for two hours; however, you can modify that amount of time by passing a value (in seconds) to $timeout.

If you have used $savedfilter and/or $savedorderby (in conjunction with $filter and/or $orderby) when you created your entity set, you can recreate it with the same reference ID even if it has been removed from 4D Server's cache.

Example

To create an entity set, which will be saved in 4D Server's cache for two hours, add $method=entityset at the end of your REST request:

GET /rest/People/?$filter="ID>320"&$method=entityset

You can create an entity set that will be stored in 4D Server's cache for only ten minutes by passing a new timeout to $timeout:

GET /rest/People/?$filter="ID>320"&$method=entityset&$timeout=600

You can also save the filter and order by, by passing true to $savedfilter and $savedorderby.

$skip and $top/$limit are not taken into consideration when saving an entity set.

After you create an entity set, the first element, __ENTITYSET, is added to the object returned and indicates the URI to use to access the entity set:

__ENTITYSET: "http://127.0.0.1:8081/rest/Employee/$entityset/9718A30BF61343C796345F3BE5B01CE7"`

$method=release

Releases an existing entity set stored in 4D Server's cache.

Description

You can release an entity set, which you created using $method=entityset, from 4D Server's cache.

Example

Release an existing entity set:

GET /rest/Employee/$entityset/4C51204DD8184B65AC7D79F09A077F24?$method=release

Response:

If the request was successful, the following response is returned:

{
"ok": true
}
If the entity set wasn't found, an error is returned:

{
"__ERROR": [
{
"message": "Error code: 1802\nEntitySet \"4C51204DD8184B65AC7D79F09A077F24\" cannot be found\ncomponent: 'dbmg'\ntask 22, name: 'HTTP connection handler'\n",
"componentSignature": "dbmg",
"errCode": 1802
}
]
}

$method=subentityset

Creates an entity set in 4D Server's cache based on the collection of related entities defined in the REST request

Description

$method=subentityset allows you to sort the data returned by the relation attribute defined in the REST request.

To sort the data, you use the $subOrderby property. For each attribute, you specify the order as ASC (or asc) for ascending order and DESC (desc) for descending order. By default, the data is sorted in ascending order.

If you want to specify multiple attributes, you can delimit them with a comma, µ, $subOrderby="lastName desc, firstName asc".

Example

If you want to retrieve only the related entities for a specific entity, you can make the following REST request where staff is the relation attribute in the Company dataclass linked to the Employee dataclass:

GET /rest/Company(1)/staff?$expand=staff&$method=subentityset&$subOrderby=lastName ASC

Response:

{

"__ENTITYSET": "/rest/Employee/$entityset/FF625844008E430B9862E5FD41C741AB",
"__entityModel": "Employee",
"__COUNT": 2,
"__SENT": 2,
"__FIRST": 0,
"__ENTITIES": [
{
"__KEY": "4",
"__STAMP": 1,
"ID": 4,
"firstName": "Linda",
"lastName": "Jones",
"birthday": "1970-10-05T14:23:00Z",
"employer": {
"__deferred": {
"uri": "/rest/Company(1)",
"__KEY": "1"
}
}
},
{
"__KEY": "1",
"__STAMP": 3,
"ID": 1,
"firstName": "John",
"lastName": "Smith",
"birthday": "1985-11-01T15:23:00Z",
"employer": {
"__deferred": {
"uri": "/rest/Company(1)",
"__KEY": "1"
}
}
}
]

}

$method=update

Updates and/or creates one or more entities

Description

$method=update allows you to update and/or create one or more entities in a single POST. If you update and/or create one entity, it is done in an object with each property an attribute with its value, e.g., { lastName: "Smith" }. If you update and/or create multiple entities, you must create a collection of objects.

In any cases, you must set the POST data in the body of the request.

To update an entity, you must pass the __KEY and __STAMP parameters in the object along with any modified attributes. If both of these parameters are missing, an entity will be added with the values in the object you send in the body of your POST.

Triggers are executed immediately when saving the entity to the server. The response contains all the data as it exists on the server.

You can also put these requests to create or update entities in a transaction by calling $atomic/$atOnce. If any errors occur during data validation, none of the entities are saved. You can also use $method=validate to validate the entities before creating or updating them.

If a problem arises while adding or modifying an entity, an error will be returned to you with that information.

note
  • Dates must be expressed in JS format: YYYY-MM-DDTHH:MM:SSZ (e.g., "2010-10-05T23:00:00Z"). If you have selected the Date only property for your Date attribute, the time zone and time (hour, minutes, and seconds) will be removed. In this case, you can also send the date in the format that it is returned to you dd!mm!yyyy (e.g., 05!10!2013).
  • Booleans are either true or false.
  • Uploaded files using $upload can be applied to an attribute of type Image or BLOB by passing the object returned in the following format { "ID": "D507BC03E613487E9B4C2F6A0512FE50"}

Example

To update a specific entity, you use the following URL:

POST /rest/Person/?$method=update

POST data:

{
__KEY: "340",
__STAMP: 2,
firstName: "Pete",
lastName: "Miller"
}

The firstName and lastName attributes in the entity indicated above will be modified leaving all other attributes (except calculated ones based on these attributes) unchanged.

If you want to create an entity, you can POST the attributes using this URL:

POST /rest/Person/?$method=update

POST data:

{ 
firstName: "John",
lastName: "Smith"
}

You can also create and update multiple entities at the same time using the same URL above by passing multiple objects in an array to the POST:

POST /rest/Person/?$method=update

POST data:

[{ 
"__KEY": "309",
"__STAMP": 5,
"ID": "309",
"firstName": "Penelope",
"lastName": "Miller"
}, {
"firstName": "Ann",
"lastName": "Jones"
}]

Response:

When you add or modify an entity, it is returned to you with the attributes that were modified. For example, if you create the new employee above, the following will be returned:

{
"__KEY": "622",
"__STAMP": 1,
"uri": "http://127.0.0.1:8081/rest/Employee(622)",
"__TIMESTAMP": "!!2020-04-03!!",
"ID": 622,
"firstName": "John",
"firstName": "Smith"
}

If, for example, the stamp is not correct, the following error is returned:

{
"__STATUS": {
"status": 2,
"statusText": "Stamp has changed",
"success": false
},
"__KEY": "1",
"__STAMP": 12,
"__TIMESTAMP": "!!2020-03-31!!",
"ID": 1,
"firstname": "Denise",
"lastname": "O'Peters",
"isWoman": true,
"numberOfKids": 1,
"addressID": 1,
"gender": true,
"imageAtt": {
"__deferred": {
"uri": "/rest/Persons(1)/imageAtt?$imageformat=best&$version=12&$expand=imageAtt",
"image": true
}
},
"extra": {
"num": 1,
"alpha": "I am 1"
},
"address": {
"__deferred": {
"uri": "/rest/Address(1)",
"__KEY": "1"
}
},
"__ERROR": [
{
"message": "Given stamp does not match current one for record# 0 of table Persons",
"componentSignature": "dbmg",
"errCode": 1263
},
{
"message": "Cannot save record 0 in table Persons of database remote_dataStore",
"componentSignature": "dbmg",
"errCode": 1046
},
{
"message": "The entity# 1 in the \"Persons\" dataclass cannot be saved",
"componentSignature": "dbmg",
"errCode": 1517
}
]
}{}