Reference documentation and code samples for the Google API Common Protos Client class FieldBehavior.
An indicator of the behavior of a given field (for example, that a field
is required in requests, or given as output but ignored as input).
This does not change the behavior in protocol buffers itself; it only
denotes the behavior and may affect how API tooling handles the field.
Note: This enum may receive new values in the future.
Protobuf type google.api.FieldBehavior
Namespace
Google \ Api
Methods
static::name
Parameter
Name
Description
value
mixed
static::value
Parameter
Name
Description
name
mixed
Constants
FIELD_BEHAVIOR_UNSPECIFIED
Value: 0
Conventional default for enums. Do not use this.
Generated from protobuf enum FIELD_BEHAVIOR_UNSPECIFIED = 0;
OPTIONAL
Value: 1
Specifically denotes a field as optional.
While all fields in protocol buffers are optional, this may be specified
for emphasis if appropriate.
Generated from protobuf enum OPTIONAL = 1;
REQUIRED
Value: 2
Denotes a field as required.
This indicates that the field must be provided as part of the request,
and failure to do so will cause an error (usually INVALID_ARGUMENT).
Generated from protobuf enum REQUIRED = 2;
OUTPUT_ONLY
Value: 3
Denotes a field as output only.
This indicates that the field is provided in responses, but including the
field in a request does nothing (the server must ignore it and
must not throw an error as a result of the field's presence).
Generated from protobuf enum OUTPUT_ONLY = 3;
INPUT_ONLY
Value: 4
Denotes a field as input only.
This indicates that the field is provided in requests, and the
corresponding field is not included in output.
Generated from protobuf enum INPUT_ONLY = 4;
IMMUTABLE
Value: 5
Denotes a field as immutable.
This indicates that the field may be set once in a request to create a
resource, but may not be changed thereafter.
Generated from protobuf enum IMMUTABLE = 5;
UNORDERED_LIST
Value: 6
Denotes that a (repeated) field is an unordered list.
This indicates that the service may provide the elements of the list
in any arbitrary order, rather than the order the user originally
provided. Additionally, the list's order may or may not be stable.
Generated from protobuf enum UNORDERED_LIST = 6;
NON_EMPTY_DEFAULT
Value: 7
Denotes that this field returns a non-empty default value if not set.
This indicates that if the user provides the empty value in a request,
a non-empty value will be returned. The user will not be aware of what
non-empty value to expect.
Generated from protobuf enum NON_EMPTY_DEFAULT = 7;
IDENTIFIER
Value: 8
Denotes that the field in a resource (a message annotated with
google.api.resource) is used in the resource name to uniquely identify the
resource. For AIP-compliant APIs, this should only be applied to the
name field on the resource.
This behavior should not be applied to references to other resources within
the message.
The identifier field of resources often have different field behavior
depending on the request it is embedded in (e.g. for Create methods name
is optional and unused, while for Update methods it is required). Instead
of method-specific annotations, only IDENTIFIER is required.
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-08-28 UTC."],[],[],null,["# Google API Common Protos Client - Class FieldBehavior (4.12.3)\n\nVersion latestkeyboard_arrow_down\n\n- [4.12.3 (latest)](/php/docs/reference/common-protos/latest/Api.FieldBehavior)\n- [4.12.2](/php/docs/reference/common-protos/4.12.2/Api.FieldBehavior)\n- [4.11.0](/php/docs/reference/common-protos/4.11.0/Api.FieldBehavior)\n- [4.10.0](/php/docs/reference/common-protos/4.10.0/Api.FieldBehavior)\n- [4.9.0](/php/docs/reference/common-protos/4.9.0/Api.FieldBehavior)\n- [4.8.3](/php/docs/reference/common-protos/4.8.3/Api.FieldBehavior) \nReference documentation and code samples for the Google API Common Protos Client class FieldBehavior.\n\nAn indicator of the behavior of a given field (for example, that a field\nis required in requests, or given as output but ignored as input).\n\nThis **does not** change the behavior in protocol buffers itself; it only\ndenotes the behavior and may affect how API tooling handles the field.\nNote: This enum **may** receive new values in the future.\n\nProtobuf type `google.api.FieldBehavior`\n\nNamespace\n---------\n\nGoogle \\\\ Api\n\nMethods\n-------\n\n### static::name\n\n### static::value\n\nConstants\n---------\n\n### FIELD_BEHAVIOR_UNSPECIFIED\n\n Value: 0\n\nConventional default for enums. Do not use this.\n\nGenerated from protobuf enum `FIELD_BEHAVIOR_UNSPECIFIED = 0;`\n\n### OPTIONAL\n\n Value: 1\n\nSpecifically denotes a field as optional.\n\nWhile all fields in protocol buffers are optional, this may be specified\nfor emphasis if appropriate.\n\nGenerated from protobuf enum `OPTIONAL = 1;`\n\n### REQUIRED\n\n Value: 2\n\nDenotes a field as required.\n\nThis indicates that the field **must** be provided as part of the request,\nand failure to do so will cause an error (usually `INVALID_ARGUMENT`).\n\nGenerated from protobuf enum `REQUIRED = 2;`\n\n### OUTPUT_ONLY\n\n Value: 3\n\nDenotes a field as output only.\n\nThis indicates that the field is provided in responses, but including the\nfield in a request does nothing (the server *must* ignore it and\n*must not* throw an error as a result of the field's presence).\n\nGenerated from protobuf enum `OUTPUT_ONLY = 3;`\n\n### INPUT_ONLY\n\n Value: 4\n\nDenotes a field as input only.\n\nThis indicates that the field is provided in requests, and the\ncorresponding field is not included in output.\n\nGenerated from protobuf enum `INPUT_ONLY = 4;`\n\n### IMMUTABLE\n\n Value: 5\n\nDenotes a field as immutable.\n\nThis indicates that the field may be set once in a request to create a\nresource, but may not be changed thereafter.\n\nGenerated from protobuf enum `IMMUTABLE = 5;`\n\n### UNORDERED_LIST\n\n Value: 6\n\nDenotes that a (repeated) field is an unordered list.\n\nThis indicates that the service may provide the elements of the list\nin any arbitrary order, rather than the order the user originally\nprovided. Additionally, the list's order may or may not be stable.\n\nGenerated from protobuf enum `UNORDERED_LIST = 6;`\n\n### NON_EMPTY_DEFAULT\n\n Value: 7\n\nDenotes that this field returns a non-empty default value if not set.\n\nThis indicates that if the user provides the empty value in a request,\na non-empty value will be returned. The user will not be aware of what\nnon-empty value to expect.\n\nGenerated from protobuf enum `NON_EMPTY_DEFAULT = 7;`\n\n### IDENTIFIER\n\n Value: 8\n\nDenotes that the field in a resource (a message annotated with\ngoogle.api.resource) is used in the resource name to uniquely identify the\nresource. For AIP-compliant APIs, this should only be applied to the\n`name` field on the resource.\n\nThis behavior should not be applied to references to other resources within\nthe message.\nThe identifier field of resources often have different field behavior\ndepending on the request it is embedded in (e.g. for Create methods name\nis optional and unused, while for Update methods it is required). Instead\nof method-specific annotations, only `IDENTIFIER` is required.\n\nGenerated from protobuf enum `IDENTIFIER = 8;`"]]