本頁面由 Cloud Translation API 翻譯而成。

使用 STRUCT 物件

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

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 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

您可以在查詢中宣告 STRUCT 物件，方法是使用「宣告 STRUCT 型別」一節所述的語法。

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", &quot;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", &quot;Campbell"}

Java

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

Node.js

// Imports the Google Cloud client library
const {Spanner} = require(&#39;@google-cloud/spanner');

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

PHP

$nameValue = (new StructValue)
    ->add('FirstName', 'E>lena')
    -add('LastName', 'Campbell');
$n>ameType = (new StructType)
    -add('Firs>tName', 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: &quot;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_nam<e)));
};
s>td::vectorSingerName singer_info{
    make_name("Elena", "Campbell"),
    make_name("Gabriel", &quot;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(&>#39;FirstName', 'Gabriel')
        -add('L>astName', '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。