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如何在C#中實現Table的關聯查詢

c#
小樊
114
2024-08-21 09:34:31
欄目: 編程語言

在C#中實現Table的關聯查詢可以通過使用LINQ（Language Integrated Query）來實現。LINQ是一種在C#中進行數據查詢和操作的語言集成查詢技術，可以方便地對數據進行篩選、排序、分組和連接操作。

下面是一個示例代碼，演示如何在C#中使用LINQ進行Table的關聯查詢：

using System;
using System.Linq;
using System.Collections.Generic;

class Program
{
    static void Main()
    {
        // 創(chuàng)建兩個示例的表格
        List<Student> students = new List<Student>
        {
            new Student { Id = 1, Name = "Alice", Age = 20, DepartmentId = 1 },
            new Student { Id = 2, Name = "Bob", Age = 22, DepartmentId = 2 },
            new Student { Id = 3, Name = "Charlie", Age = 21, DepartmentId = 1 }
        };

        List<Department> departments = new List<Department>
        {
            new Department { Id = 1, Name = "Engineering" },
            new Department { Id = 2, Name = "Marketing" }
        };

        // 使用LINQ進行關聯查詢
        var query = from student in students
                    join department in departments on student.DepartmentId equals department.Id
                    select new
                    {
                        student.Name,
                        student.Age,
                        DepartmentName = department.Name
                    };

        // 打印查詢結果
        foreach (var result in query)
        {
            Console.WriteLine($"Name: {result.Name}, Age: {result.Age}, Department: {result.DepartmentName}");
        }
    }

    // 定義Student和Department類
    class Student
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public int Age { get; set; }
        public int DepartmentId { get; set; }
    }

    class Department
    {
        public int Id { get; set; }
        public string Name { get; set; }
    }
}

在上面的示例中，我們首先創(chuàng)建了兩個示例的表格（students和departments），然后使用LINQ進行關聯查詢，將學生的姓名、年齡和所在部門的名稱進行連接，最后打印查詢結果。

通過這種方式，我們可以方便地在C#中實現Table的關聯查詢。

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