Cloud Datastore API - php - GqlQuery - 绑定参数

Question

我正在尝试将一些参数绑定到我的 GQL 查询字符串。 当我在不绑定任何东西的情况下运行查询时一切都很好：

$result = $DB->query_entities("SELECT * FROM kind WHERE fieldName = 4 限制 1");

但我不知道如何绑定一些参数。这就是我尝试这样做的方式：

function query_entities($query_string, $args=[]){       
    $gql_query = new Google_Service_Datastore_GqlQuery();
    $gql_query->setQueryString($query_string);
    $gql_query->setAllowLiteral(true);

    if( !empty($args) ){
        $binding_args = [];

        foreach ($args as $key => $value) {
            $binding_value = new Google_Service_Datastore_Value();
            $binding_value->setIntegerValue($value);

            $arg = new Google_Service_Datastore_GqlQueryArg();
            $arg->setName($key);
            $arg->setValue($binding_value);

            $binding_args[] = $arg;
        }

        $gql_query->setNameArgs($binding_args);
    }

        $req = new Google_Service_Datastore_RunQueryRequest();
        $req->setGqlQuery($gql_query);

        return $this->dataset->runQuery($this->dataset_id, $req, []);
}

$exampleValue = 4;

$result = $DB->query_entities("SELECT * FROM kind WHERE fieldName = :fieldName LIMIT 1", ["fieldName" => $exampleValue]);

或者：

function query_entities($query_string, $args=[]){       
    $gql_query = new Google_Service_Datastore_GqlQuery();
    $gql_query->setQueryString($query_string);
    $gql_query->setAllowLiteral(true);

    if( !empty($args) ){
        $binding_args = [];

        foreach ($args as $value) {
            $binding_value = new Google_Service_Datastore_Value();
            $binding_value->setIntegerValue($value);

            $arg = new Google_Service_Datastore_GqlQueryArg();
            $arg->setValue($binding_value);

            $binding_args[] = $arg;
        }

        $gql_query->setNumberArgs($binding_args);
    }

        $req = new Google_Service_Datastore_RunQueryRequest();
        $req->setGqlQuery($gql_query);

        return $this->dataset->runQuery($this->dataset_id, $req, []);
}

$exampleValue = 4;

$result = $DB->query_entities("SELECT * FROM kind WHERE fieldName = :1 LIMIT 1", [$exampleValue]);

这是我得到的： '调用 POST https://www.googleapis.com/datastore/v1beta2/datasets/age-of-deployment/runQuery 时出错：(400) 第 1 行第 52 列出现词法错误。遇到：":" (58)，之后：""' in ...

Answer 1

Cloud Datastore GQL 和 Python GQL (App Engine) 处理参数绑定略有不同。

在这种情况下，您需要使用@ 而不是:，例如：

SELECT * FROM kind WHERE fieldName = @fieldName LIMIT 1

或

SELECT * FROM kind WHERE fieldName = @1 LIMIT 1

这是 Cloud Datastore GQL 中用于参数绑定的 reference documentation。