要获得与亚马逊 Timestream 类似的功能 LiveAnalytics，可以考虑适用于 InfluxDB 的亚马逊 Timestream。适用于 InfluxDB 的 Amazon Timestream 提供简化的数据摄取和个位数毫秒级的查询响应时间，以实现实时分析。点击[此处](https://docs.aws.amazon.com//timestream/latest/developerguide/timestream-for-influxdb.html)了解更多信息。

本文属于机器翻译版本。若本译文内容与英语原文存在差异，则一律以英文原文为准。

# 列出数据库
<a name="code-samples.list-db"></a>

可使用以下代码段列出数据库。

**注意**  
这些代码段基于 [GitHub](https://github.com/awslabs/amazon-timestream-tools/blob/master/sample_apps) 上的完整示例应用程序。有关如何开始使用示例应用程序的更多信息，请参阅 [示例应用程序](sample-apps.md)。

------
#### [  Java  ]

```
    public void listDatabases() {
        System.out.println("Listing databases");
        ListDatabasesRequest request = new ListDatabasesRequest();
        ListDatabasesResult result = amazonTimestreamWrite.listDatabases(request);
        final List<Database> databases = result.getDatabases();
        printDatabases(databases);

        String nextToken = result.getNextToken();
        while (nextToken != null && !nextToken.isEmpty()) {
            request.setNextToken(nextToken);
            ListDatabasesResult nextResult = amazonTimestreamWrite.listDatabases(request);
            final List<Database> nextDatabases = nextResult.getDatabases();
            printDatabases(nextDatabases);
            nextToken = nextResult.getNextToken();
        }
    }
    
    private void printDatabases(List<Database> databases) {
        for (Database db : databases) {
            System.out.println(db.getDatabaseName());
        }
    }
```

------
#### [  Java v2  ]

```
    public void listDatabases() {
        System.out.println("Listing databases");
        ListDatabasesRequest request = ListDatabasesRequest.builder().maxResults(2).build();
        ListDatabasesIterable listDatabasesIterable = timestreamWriteClient.listDatabasesPaginator(request);
        for(ListDatabasesResponse listDatabasesResponse : listDatabasesIterable) {
            final List<Database> databases = listDatabasesResponse.databases();
            databases.forEach(database -> System.out.println(database.databaseName()));
        }
    }
```

------
#### [  Go  ]

```
// List databases.
    listDatabasesMaxResult := int64(15)

    listDatabasesInput := &timestreamwrite.ListDatabasesInput{
        MaxResults: &listDatabasesMaxResult,
    }

    listDatabasesOutput, err := writeSvc.ListDatabases(listDatabasesInput)

    if err != nil {
        fmt.Println("Error:")
        fmt.Println(err)
    } else {
        fmt.Println("List databases is successful, below is the output:")
        fmt.Println(listDatabasesOutput)
    }
```

------
#### [  Python  ]

```
    def list_databases(self):
        print("Listing databases")
        try:
            result = self.client.list_databases(MaxResults=5)
            self._print_databases(result['Databases'])
            next_token = result.get('NextToken', None)
            while next_token:
                result = self.client.list_databases(NextToken=next_token, MaxResults=5)
                self._print_databases(result['Databases'])
                next_token = result.get('NextToken', None)
        except Exception as err:
            print("List databases failed:", err)
```

------
#### [  Node.js  ]

以下代码段使用 AWS SDK for JavaScript v3。有关如何安装客户端和使用情况的更多信息，请参阅 [Timestream 写入客户端：AWS SDK for JavaScript v3](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/clients/client-timestream-write/index.html)。

另请参阅 [Class ListDatabasesCommand](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/clients/client-timestream-write/classes/listdatabasescommand.html) 和 [ListDatabases](https://docs.aws.amazon.com/timestream/latest/developerguide/API_ListDatabases.html)。

```
import { TimestreamWriteClient, ListDatabasesCommand } from "@aws-sdk/client-timestream-write";
const writeClient = new TimestreamWriteClient({ region: "us-east-1" });

const params = {
    MaxResults: 15
};

const command = new ListDatabasesCommand(params);

getDatabasesList(null);

async function getDatabasesList(nextToken) {
    if (nextToken) {
        params.NextToken = nextToken;
    }

    try {
        const data = await writeClient.send(command);

        data.Databases.forEach(function (database) {
            console.log(database.DatabaseName);
        });

        if (data.NextToken) {
            return getDatabasesList(data.NextToken);
        }
    } catch (error) {
        console.log("Error while listing databases", error);
    }
}
```

以下代码段使用 AWS SDK for JavaScript V2 风格。该代码段基于示例应用程序，该应用程序位于 [GitHub 上的 Node.js 示例适用于 LiveAnalytics 的 Amazon Timestream 应用程序](https://github.com/awslabs/amazon-timestream-tools/tree/mainline/sample_apps/js)。

```
async function listDatabases() {
    console.log("Listing databases:");
    const databases = await getDatabasesList(null);
    databases.forEach(function(database){
        console.log(database.DatabaseName);
    });
}

function getDatabasesList(nextToken, databases = []) {
    var params = {
        MaxResults: 15
    };

    if(nextToken) {
        params.NextToken = nextToken;
    }

    return writeClient.listDatabases(params).promise()
        .then(
            (data) => {
                databases.push.apply(databases, data.Databases);
                if (data.NextToken) {
                    return getDatabasesList(data.NextToken, databases);
                } else {
                    return databases;
                }
            },
            (err) => {
                console.log("Error while listing databases", err);
            });
}
```

------
#### [  .NET  ]

```
        public async Task ListDatabases()
        {
            Console.WriteLine("Listing Databases");

            try
            {
                var listDatabasesRequest = new ListDatabasesRequest
                {
                    MaxResults = 5
                };
                ListDatabasesResponse response = await writeClient.ListDatabasesAsync(listDatabasesRequest);
                PrintDatabases(response.Databases);
                var nextToken = response.NextToken;
                while (nextToken != null)
                {
                    listDatabasesRequest.NextToken = nextToken;
                    response = await writeClient.ListDatabasesAsync(listDatabasesRequest);
                    PrintDatabases(response.Databases);
                    nextToken = response.NextToken;
                }
            }
            catch (Exception e)
            {
                Console.WriteLine("List database failed:" + e.ToString());
            }

        }
```

------