Question

我有一个表：digital_asset，它的分区键是：id。它有一个全局二级索引：带分区键的ean-index：ean。我希望能够使用dynastyjs使用二级索引查询表。使用aws-sdk，我会这样做：

return new Promise(function (resolve, reject) {
    var params = {
        TableName: "digital_asset",
        IndexName: "ean-index",
        KeyConditionExpression: "ean = :ean",
        ExpressionAttributeValues: {
            ":ean": ean
        },
        ProjectionExpression: "id, ean"
    };
    docClient.query(params, function(err, data) {
        if (err)
            console.error(JSON.stringify(err, null, 2));
        else
            console.log(JSON.stringify(data, null, 2));
        if (!err) {
            resolve(data.Items.map(function(item){return item.id}));
        } else {
            reject(err);
        }
    });
});

使用dynasty更好，例如这里是由主索引搜索的查询：

return new Promise(function (resolve) {
    return digital_asset.find(asset_id).then(function (item) {
        resolve(item.ean);
    });
});

这是我尝试过的，但是出现了错误：

return new Promise(function (resolve, reject) {
   return digital_asset.findAll({"ean-index":ean}).then(function (item) {
       resolve(item.id);
   }).catch(reject);
});

错误：

InvalidParameterType: Expected params.KeyConditions['id'].AttributeValueList[0].S to be a string
    at ParamValidator.fail (node_modules/aws-sdk/lib/param_validator.js:50:37)
    at ParamValidator.validateType (node_modules/aws-sdk/lib/param_validator.js:218:10)
    at ParamValidator.validateString (node_modules/aws-sdk/lib/param_validator.js:150:14)
    at ParamValidator.validateScalar (node_modules/aws-sdk/lib/param_validator.js:130:21)
    at ParamValidator.validateMember (node_modules/aws-sdk/lib/param_validator.js:94:21)
    at ParamValidator.validateStructure (node_modules/aws-sdk/lib/param_validator.js:75:14)
    at ParamValidator.validateMember (node_modules/aws-sdk/lib/param_validator.js:88:21)
    at ParamValidator.validateList (node_modules/aws-sdk/lib/param_validator.js:103:14)
    at ParamValidator.validateMember (node_modules/aws-sdk/lib/param_validator.js:90:21)
    at ParamValidator.validateStructure (node_modules/aws-sdk/lib/param_validator.js:75:14)
    at ParamValidator.validateMember (node_modules/aws-sdk/lib/param_validator.js:88:21)
    at ParamValidator.validateMap (node_modules/aws-sdk/lib/param_validator.js:117:14)
    at ParamValidator.validateMember (node_modules/aws-sdk/lib/param_validator.js:92:21)
    at ParamValidator.validateStructure (node_modules/aws-sdk/lib/param_validator.js:75:14)
    at ParamValidator.validateMember (node_modules/aws-sdk/lib/param_validator.js:88:21)
    at ParamValidator.validate (node_modules/aws-sdk/lib/param_validator.js:34:10)
    at Request.VALIDATE_PARAMETERS (node_modules/aws-sdk/lib/event_listeners.js:89:42)
    at Request.callListeners (node_modules/aws-sdk/lib/sequential_executor.js:105:20)
    at callNextListener (node_modules/aws-sdk/lib/sequential_executor.js:95:12)
    at node_modules/aws-sdk/lib/event_listeners.js:75:9
    at finish (node_modules/aws-sdk/lib/config.js:307:7)
    at node_modules/aws-sdk/lib/config.js:323:9
    at Credentials.get (node_modules/aws-sdk/lib/credentials.js:126:7)
    at getAsyncCredentials (node_modules/aws-sdk/lib/config.js:317:24)
    at Config.getCredentials (node_modules/aws-sdk/lib/config.js:337:9)
    at Request.VALIDATE_CREDENTIALS (node_modules/aws-sdk/lib/event_listeners.js:70:26)
    at Request.callListeners (node_modules/aws-sdk/lib/sequential_executor.js:101:18)
    at Request.emit (node_modules/aws-sdk/lib/sequential_executor.js:77:10)
    at Request.emit (node_modules/aws-sdk/lib/request.js:661:14)
    at Request.transition (node_modules/aws-sdk/lib/request.js:22:10)
    at AcceptorStateMachine.runTo (node_modules/aws-sdk/lib/state_machine.js:14:12)
    at Request.runTo (node_modules/aws-sdk/lib/request.js:394:15)
    at Request.send (node_modules/aws-sdk/lib/request.js:358:10)
    at makeRequest (node_modules/aws-sdk/lib/service.js:180:27)
    at svc.(anonymous function) [as query] (node_modules/aws-sdk/lib/service.js:437:23)
    at tryCatcher (node_modules/dynasty/node_modules/bluebird/js/main/util.js:26:23)
    at ret [as queryAsync] (eval at <anonymous> (node_modules/dynasty/node_modules/bluebird/js/main/promisify.js:163:12), <anonymous>:13:39)
    at Table.module.exports.queryByHashKey (node_modules/dynasty/lib/lib/aws-translators.js:142:31)
    at tryCatcher (node_modules/dynasty/node_modules/bluebird/js/main/util.js:26:23)
    at Promise._settlePromiseFromHandler (node_modules/dynasty/node_modules/bluebird/js/main/promise.js:507:31)
    at Promise._settlePromiseAt (node_modules/dynasty/node_modules/bluebird/js/main/promise.js:581:18)
    at Promise._settlePromises (node_modules/dynasty/node_modules/bluebird/js/main/promise.js:697:14)
    at Async._drainQueue (node_modules/dynasty/node_modules/bluebird/js/main/async.js:123:16)
    at Async._drainQueues (node_modules/dynasty/node_modules/bluebird/js/main/async.js:133:10)
    at Immediate.Async.drainQueues (node_modules/dynasty/node_modules/bluebird/js/main/async.js:15:14)

Answer 1

我也正在研究使用Dynasty的全球二级索引。查看他们的源代码（特别是aws-translators.coffee v1.0 around line 135）。看起来您可能需要执行类似.query({ indexName: "ean-index" })的操作。

dynastyjs：如何使用二级全局索引查找项目

1 个答案: