如何创建带有全局二级索引的表dynamodb

Question

我想通过 dynamoDB 创建表

User

，其中包含一些由 swagger 设计的属性：

User {
   id (string, optional): UUID of User ,
   name (string, optional),
   lastLoginedAt (string, optional),
   avatar (Avatar, optional),
}

Avatar {
   avatarId (string, optional):,
   iconUri (string, optional),
   message (string, optional),
}

并且想要

User

将在 putItem 之后以 json 响应，如下所示：

{
"id": "string",
"name": "string",
"lastLoginedAt": "2016-06-24 15:28:26",
"avatar": {
  "avatarId": "string",
  "iconUri": "string",
  "message": "string"
},
}

我是 Dynamodb 初学者，我仍然坚持创建表，这是我的代码：

$dynamodb->createTable([
'TableName' => 'User',
'AttributeDefinitions' => [
    [ 'AttributeName' => 'id', 'AttributeType' => 'S' ],
    [ 'AttributeName' => 'name', 'AttributeType' => 'S' ],
    [ 'AttributeName' => 'avatar', 'AttributeType' => 'S' ]
],
'KeySchema' => [
    [ 'AttributeName' => 'id', 'KeyType' => 'HASH' ],  
    [ 'AttributeName' => 'name', 'KeyType' => 'RANGE' ]
],
'GlobalSecondaryIndexes' => [
    [
        'IndexName' => 'avatarIndex',
        'KeySchema' => [
            [ 'AttributeName' => 'avatarId', 'KeyType' => 'HASH' ],  
            [ 'AttributeName' => 'id', 'KeyType' => 'RANGE' ] 
        ],
        'Projection' => [ 
            'ProjectionType' => 'INCLUDE',
            'NonKeyAttributes' => [ 'iconUri', 'message' ]
        ],
        'ProvisionedThroughput' => [
            'ReadCapacityUnits' => 5,
            'WriteCapacityUnits' => 5
        ]
    ]
],
'ProvisionedThroughput' => [
    'ReadCapacityUnits' => 5,
    'WriteCapacityUnits' => 5
]]);

这是错误：

local.ERROR: Error executing "CreateTable" on "http://172.18.0.5:8000"; AWS HTTP error: Client error: `POST http://172.18.0.5:8000` resulted in a `400 Bad Request` response:{"__type":"com.amazon.coral.validate#ValidationException","message":"Global Secondary Index hash key not specified in At (truncated...)
ValidationException (client): Global Secondary Index hash key not   specified in Attribute Definitons.Type unknown. - {"__type":"com.amazon.coral.validate#ValidationException","message":"Global Secondary Index hash key not specified in Attribute Definitons.Type unknown."}

提前致谢！

Answer 1

根据错误，您似乎忘记在主表中添加属性，以下代码应该可以工作

$dynamodb->createTable([
'TableName' => 'User',
'AttributeDefinitions' => [
    [ 'AttributeName' => 'id', 'AttributeType' => 'S' ], 
    [ 'AttributeName' => 'name', 'AttributeType' => 'S' ],
    [ 'AttributeName' => 'avatar', 'AttributeType' => 'S' ],
    [ 'AttributeName' => 'avatarId', 'AttributeType' => 'S' ], // this attribute was missing  

],
'KeySchema' => [
    [ 'AttributeName' => 'id', 'KeyType' => 'HASH' ],  
    [ 'AttributeName' => 'name', 'KeyType' => 'RANGE' ]
],
'GlobalSecondaryIndexes' => [
    [
        'IndexName' => 'avatarIndex',
        'KeySchema' => [
            [ 'AttributeName' => 'avatarId', 'KeyType' => 'HASH' ],  
            [ 'AttributeName' => 'id', 'KeyType' => 'RANGE' ] 
        ],
        'Projection' => [ 
            'ProjectionType' => 'INCLUDE',
            'NonKeyAttributes' => [ 'iconUri', 'message' ]
        ],
        'ProvisionedThroughput' => [
            'ReadCapacityUnits' => 5,
            'WriteCapacityUnits' => 5
        ]
    ]
],
'ProvisionedThroughput' => [
    'ReadCapacityUnits' => 5,
    'WriteCapacityUnits' => 5
]]);

您必须在主表属性定义中包含 GSI 的哈希和范围属性。除此之外，正如 Lokesh 提到的，您可以为 Avatar 对象使用 StringSet 数据类型。

希望有帮助。

Answer 2

在 Dynamodb 中，您无法保存复杂的对象。在您的情况下，您无法将其保存为复杂的对象。

但是您可以将头像对象 JSON 保存为字符串，并且头像将仅是字符串类型的列。

将任何 JSON 保存为字符串后，您将无法在 JSON 内创建属性的索引。

在您的情况下，您不应该以 json 格式保存头像。您可以创建 avatarId、avatarIconUri 和 avatarMessage 等列。

{
"id": "string",
"name": "string",
"lastLoginedAt": "2016-06-24 15:28:26",
"avatarId": "string",
"avatarIconUri": "string",
"avatarMessage": "string"
}



GlobalSecondaryIndexes' => [
    [
        'IndexName' => 'avatarIndex',
        'KeySchema' => [
            [ 'AttributeName' => 'avatarId', 'KeyType' => 'HASH' ],  
            [ 'AttributeName' => 'id', 'KeyType' => 'RANGE' ] 
        ],
        'Projection' => [ 
            'ProjectionType' => 'INCLUDE',
            'NonKeyAttributes' => [ 'avatarIconUri', 'avatarMessage' ]
        ],
        'ProvisionedThroughput' => [
            'ReadCapacityUnits' => 5,
            'WriteCapacityUnits' => 5
        ]
    ]
],

Answer 3

我在尝试创建名称中带有 - 的全局二级索引时遇到此错误 - 显然对于列名来说是可以的。