Cloud Datastore Client - Class Key (1.33.1)

Reference documentation and code samples for the Cloud Datastore Client class Key.

Keys are unique identifiers for entities.

Keys may be considered either "named" or "incomplete". A named Key is one in which each element of the Key path specify a Kind and a Name or ID. An incomplete Key omits the Name or ID from the final path element.

Named Keys are required for any lookup, update, upsert or delete operations. They may also be used for inserting records, so long as you are certain that the identifier is available in Datastore.

Incomplete Keys may be used for inserting records into Datastore. When an incomplete Key is used, Datastore will allocate an ID before inserting.

Incomplete Keys are useful for guaranteeing the availability of an identifier without requiring an additional operation to check whether a given name or ID is available.

Key state can be checked by calling Key::state() . The return will be one of Key::STATE_NAMED or Key::STATE_INCOMPLETE .

Example:

 use Google\Cloud\Datastore\DatastoreClient;

$datastore = new DatastoreClient();

$key = $datastore->key('Person', 'Bob'); 

 // Keys with complex paths can be constructed with additional method calls.

$key = $datastore->key('Person', 'Bob');
$key->ancestor('Parents', 'Joe');
$key->ancestor('Grandparents', 'Barb'); 

 // Path elements can also be appended, so long as the current last path
// element contains a kind and identifier.

$key = $datastore->key('Grandparents', 'Barb');
$key->pathElement('Parents', 'Joe');
$key->pathElement('Person');
$key->pathElement('Child', 'Dave'); // Error here. 

Create a Key.

See also:

• PathElement

See also:

• PathElement

Use another Key's path as the current Key's ancestor

Given key path will be prepended to any path elements on the current key.

Example:

 $parent = $datastore->key('Person', 'Dad');
$key->ancestorKey($parent); 

Check if the Key is considered Named or Incomplete.

Use Key::STATE_NAMED and Key::STATE_INCOMPLETE to check value.

Example:

 // An incomplete key does not have an ID on its last path element.
$key = $datastore->key('parent', 1234)
    ->pathElement('child');

if ($key->state() === Key::STATE_INCOMPLETE) {
    echo 'Key is incomplete!';
} 

 // A named key has a kind and an identifier on each path element.
$key = $datastore->key('parent', 1234)
    ->pathElement('child', 4321);

if ($key->state() === Key::STATE_NAMED) {
    echo 'Key is named!';
} 

Set the value of the last path element in a Key

This method is used internally when IDs are allocated to existing instances of a Key. It should not generally be used externally.

Example:

 $key = $datastore->key('Person');
$key->setLastElementIdentifier('Bob', Key::TYPE_NAME); 

Get the key path

Example:

 $path = $key->path(); 

Get the last pathElement in the key

Example:

 $lastPathElement = $key->pathEnd(); 

Get the last pathElement identifier.

If the key is incomplete, returns null .

Example:

 $lastPathElementIndentifier = $key->pathEndIdentifier(); 

Get the last pathElement identifier type.

If the key is incomplete, returns null .

Example:

 $lastPathElementIdentifierType = $key->pathEndIdentifierType(); 

Get the key object formatted for the datastore service.

Represent the path as a string.