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首页 > 解决方案 > 在 Ballerina 中访问表数据结构时出现问题。错误无效操作...不支持非必填字段的字段访问

wso2 - 在 Ballerina 中访问表数据结构时出现问题。错误无效操作...不支持非必填字段的字段访问

问题描述

我一直在学习芭蕾舞女演员，并且一直在学习这些例子。我在Ballerina By Example - Tables的文档中遇到以下示例的问题。

示例（和我的）中的代码如下：

import ballerina/io;
import ballerina/jsonutils;
import ballerina/xmlutils;

type Employee record {
    int id;
    string name;
    float salary;
};

public function main() {

    table<Employee> tbEmployee = table {
        {key id, name, salary},
        [
            {1, "Mary", 300.5},
            {2, "John", 200.5},
            {3, "Jim", 330.5}
        ]
    };

    io:print("Table Information: ");
    io:println(tbEmployee);

    Employee e1 = {id: 1, name: "Jane", salary: 300.50};
    Employee e2 = {id: 2, name: "Anne", salary: 100.50};
    Employee e3 = {id: 3, name: "John", salary: 400.50};
    Employee e4 = {id: 4, name: "Peter", salary: 150.0};

    table<Employee> tb = table {
        {key id, name, salary},
        [
            e1,
            e2
        ]
    };

    Employee[] employees = [e3, e4];

    foreach var emp in employees {
        var ret = tb.add(emp);
        if (ret is ()) {
            io:println("Adding record to table successful");
        } else {
            io:println("Adding to table failed: ", ret.reason());
        }
    }

    io:println("Table Information: ", tb);

    io:println("Using foreach: ");
    foreach var x in tb {
        io:println("Name: ", x.name);
    }

    io:println("Using while loop: ");
    while (tb.hasNext()) {
        var ret = tb.getNext();
        io:println("Name: ", ret.name);
    }

    json retValJson = jsonutils:fromTable(tb);
    io:println("JSON: ", retValJson.toJsonString());

    xml retValXml = xmlutils:fromTable(tb);
    io:println("XML: ", retValXml);

    int|error count = tb.remove(isHigherSalary);
    io:println("Deleted Count: ", count);

    io:println(tb);
}

function isHigherSalary(Employee emp) returns boolean {
    return emp.salary > 300.0;
}

当我运行它时，我遇到以下行 (59) 的问题：

io:println("Name: ", ret.name);

error: .::tables_orig.bal:59:30: invalid operation: type 'record {| anydata...; |}' does not support field access for non-required field 'name'

我正在使用芭蕾舞女演员 1.0.5。我怎样才能解决这个问题？

标签： wso2ballerina

解决方案

理想情况下，字段访问应该与 一起使用getNext()，但是在如何确定getNext()调用的类型方面存在问题。现已通过https://github.com/ballerina-platform/ballerina-lang/commit/8196d93023ba12958dfdd5f28a70c8da2147bf48修复此问题，该修复程序将在即将发布的 Ballerina 1.1.0 中提供。

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