本頁面由 Cloud Translation API 翻譯而成。

使用 STRUCT 物件

PostgreSQL 介面注意事項： STRUCT 資料類型不受 Spanner 適用的 PostgreSQL 介面支援。

Spanner 可讓您從資料建立 STRUCT 物件，或是在以 Spanner 用戶端程式庫執行 SQL 查詢時，將 STRUCT 物件做為繫結參數使用。

如要進一步瞭解 Spanner 中的 STRUCT 類型，請參閱「資料類型」一文。

宣告 STRUCT 物件的使用者定義類型

您可以使用「宣告 STRUCT 類型」一文所述的語法，在查詢中宣告 STRUCT 物件。

您可以將 STRUCT 物件的類型定義為欄位名稱和物件資料類型的序列，接著就可以將類型套用至包含 STRUCT 類型參數繫結的查詢，Spanner 會使用這個類型來確認查詢中的 STRUCT 參數值是否有效。

C++

// Cloud Spanner STRUCT<> types are represented by std::tuple<...>. The
// following represents a STRUCT<> with two unnamed STRING fields.
using NameType = std::tuple<std::string, std::string>;

C#

var nameType = new SpannerStruct
{
    { "FirstName", SpannerDbType.String, null},
    { "LastName", SpannerDbType.String, null}
};

Go


type nameType struct {
	FirstName string
	LastName  string
}

Java

Type nameType =
    Type.struct(
        Arrays.asList(
            StructField.of("FirstName", Type.string()),
            StructField.of("LastName", Type.string())));

Node.js

const nameType = {
  type: 'struct',
  fields: [
    {
      name: 'FirstName',
      type: 'string',
    },
    {
      name: 'LastName',
      type: 'string',
    },
  ],
};

PHP

$nameType = new ArrayType(
    (new StructType)
        ->add('FirstName', Database::TYPE_STRING)
        ->add('LastName', Database::TYPE_STRING)
);

Python

name_type = param_types.Struct(
    [
        param_types.StructField("FirstName", param_types.STRING),
        param_types.StructField("LastName", param_types.STRING),
    ]
)

Ruby

name_type = client.fields FirstName: :STRING, LastName: :STRING

建立 STRUCT 物件

以下範例顯示如何使用 Spanner 用戶端程式庫建立 STRUCT 物件。

C++

// Cloud Spanner STRUCT<> types are represented by std::tuple<...>. The
// following represents a STRUCT<> with two unnamed STRING fields.
using NameType = std::tuple<std::string, std::string>;
auto singer_info = NameType{"Elena", "Campbell"};

C#

var nameStruct = new SpannerStruct
{
    { "FirstName", SpannerDbType.String, "Elena" },
    { "LastName", SpannerDbType.String, "Campbell" },
};

Go


type name struct {
	FirstName string
	LastName  string
}
var singerInfo = name{"Elena", "Campbell"}

Java

Struct name =
    Struct.newBuilder().set("FirstName").to("Elena").set("LastName").to("Campbell").build();

Node.js

// Imports the Google Cloud client library
const {Spanner} = require('@google-cloud/spanner');

const nameStruct = Spanner.struct({
  FirstName: 'Elena',
  LastName: 'Campbell',
});

PHP

$nameValue = (new StructValue)
    ->add('FirstName', 'Elena')
    ->add('LastName', 'Campbell');
$nameType = (new StructType)
    ->add('FirstName', Database::TYPE_STRING)
    ->add('LastName', Database::TYPE_STRING);

Python

record_type = param_types.Struct(
    [
        param_types.StructField("FirstName", param_types.STRING),
        param_types.StructField("LastName", param_types.STRING),
    ]
)
record_value = ("Elena", "Campbell")

Ruby

name_struct = { FirstName: "Elena", LastName: "Campbell" }

您也可以使用用戶端程式庫建立 STRUCT 物件的陣列，如以下範例所示：

C++

// Cloud Spanner STRUCT<> types with named fields are represented by
// std::tuple<std::pair<std::string, T>...>, create an alias to make it easier
// to follow this code.
using SingerName = std::tuple<std::pair<std::string, std::string>,
                              std::pair<std::string, std::string>>;
auto make_name = [](std::string first_name, std::string last_name) {
  return std::make_tuple(std::make_pair("FirstName", std::move(first_name)),
                         std::make_pair("LastName", std::move(last_name)));
};
std::vector<SingerName> singer_info{
    make_name("Elena", "Campbell"),
    make_name("Gabriel", "Wright"),
    make_name("Benjamin", "Martinez"),
};

C#

var bandMembers = new List<SpannerStruct>
{
    new SpannerStruct { { "FirstName", SpannerDbType.String, "Elena" }, { "LastName", SpannerDbType.String, "Campbell" } },
    new SpannerStruct { { "FirstName", SpannerDbType.String, "Gabriel" }, { "LastName", SpannerDbType.String, "Wright" } },
    new SpannerStruct { { "FirstName", SpannerDbType.String, "Benjamin" }, { "LastName", SpannerDbType.String, "Martinez" } },
};

Go


var bandMembers = []nameType{
	{"Elena", "Campbell"},
	{"Gabriel", "Wright"},
	{"Benjamin", "Martinez"},
}

Java

List<Struct> bandMembers = new ArrayList<>();
bandMembers.add(
    Struct.newBuilder().set("FirstName").to("Elena").set("LastName").to("Campbell").build());
bandMembers.add(
    Struct.newBuilder().set("FirstName").to("Gabriel").set("LastName").to("Wright").build());
bandMembers.add(
    Struct.newBuilder().set("FirstName").to("Benjamin").set("LastName").to("Martinez").build());

Node.js

const bandMembersType = {
  type: 'array',
  child: nameType,
};

const bandMembers = [
  Spanner.struct({
    FirstName: 'Elena',
    LastName: 'Campbell',
  }),
  Spanner.struct({
    FirstName: 'Gabriel',
    LastName: 'Wright',
  }),
  Spanner.struct({
    FirstName: 'Benjamin',
    LastName: 'Martinez',
  }),
];

PHP

$bandMembers = [
    (new StructValue)
        ->add('FirstName', 'Elena')
        ->add('LastName', 'Campbell'),
    (new StructValue)
        ->add('FirstName', 'Gabriel')
        ->add('LastName', 'Wright'),
    (new StructValue)
        ->add('FirstName', 'Benjamin')
        ->add('LastName', 'Martinez')
];

Python

band_members = [
    ("Elena", "Campbell"),
    ("Gabriel", "Wright"),
    ("Benjamin", "Martinez"),
]

Ruby

band_members = [name_type.struct(["Elena", "Campbell"]),
                name_type.struct(["Gabriel", "Wright"]),
                name_type.struct(["Benjamin", "Martinez"])]

在 SQL 查詢結果中傳回 STRUCT 物件

進行 Spanner SQL 查詢時，部分查詢可將 STRUCT 物件的陣列傳回資料列。詳情請參閱「將 STRUCT 與 SELECT 搭配使用」。

以 STRUCT 物件做為 SQL 查詢的繫結參數

您可以將 STRUCT 物件當做 SQL 查詢的繫結參數。如要進一步瞭解參數，請參閱「查詢參數」一節。