創(chuàng)建模型

TopBasePoco是框架所有模型的基類，它只定義了一個(gè)Guid的主鍵，所有其他模型都必須直接或間接繼承TopBasePoco，否則框架的其他自動(dòng)化操作無(wú)法執(zhí)行

這意味著框架只支持Guid為唯一主鍵的數(shù)據(jù)庫(kù)設(shè)計(jì)，雖然不同的人對(duì)此有不同的看法，但其實(shí)任何表的設(shè)計(jì)都不妨礙再加一個(gè)Guid的主鍵

BasePoco是框架所有內(nèi)置模型的基類，它在TopBasePoco的基礎(chǔ)上增加了創(chuàng)建人，修改人，創(chuàng)建時(shí)間和修改時(shí)間四個(gè)字段，對(duì)于大多數(shù)模型，這些字段都是需要的

建議用戶自定義的模型都繼承BasePoco

框架自帶的添加和修改操作會(huì)自動(dòng)更新創(chuàng)建人，修改人，創(chuàng)建時(shí)間和修改時(shí)間這些字段

PersistPoco在BasePoco的基礎(chǔ)上增加了IsValid字段，指示框架對(duì)這類模型進(jìn)行假刪除

框架自帶的刪除功能會(huì)自動(dòng)將繼承PersistPoco的模型的IsValid字段設(shè)為false，而不會(huì)真正刪除它

模型之間的一對(duì)多和多對(duì)多的關(guān)系完全遵從EF Core默認(rèn)的規(guī)則

初次使用者容易忘記定義外鍵名稱，比如定義了一個(gè)指向School類的屬性叫做ParentSchool，那么必須有一個(gè)叫做ParentSchoolId的guid屬性定義外鍵名稱，這是EF Core的默認(rèn)規(guī)則

如果不定義這個(gè)加Id的字段，雖然數(shù)據(jù)庫(kù)可以生成，但是在代碼層面是不知道外鍵名稱的，框架的代碼生成器也就無(wú)法正常工作

以下代碼創(chuàng)建了一個(gè)學(xué)校模型，一個(gè)專業(yè)模型和一個(gè)學(xué)生模型

學(xué)校和專業(yè)之間是一對(duì)多的關(guān)系，學(xué)生和專業(yè)之間是多對(duì)多的關(guān)系，通過(guò)中間表StudentMajor關(guān)聯(lián)

請(qǐng)注意這些關(guān)聯(lián)關(guān)系的定義，比如School和ShoolId，Major和MajorId，Student和StudentId這些都是成對(duì)出現(xiàn)的

StudentMajor模型上的[MiddleTable]標(biāo)記，表示這是一張多對(duì)多的中間表，在中間表上加[MiddleTable]可以讓代碼生成器識(shí)別多對(duì)多的關(guān)系并生成正確的代碼

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Text;
using WalkingTec.Mvvm.Core;
namespace FirstProject.Model
{
    public enum SchoolTypeEnum {
        [Display(Name = "公立學(xué)校")]
        PUB,
        [Display(Name = "私立學(xué)校")]
        PRI
    }
    public class School : BasePoco
    {
        [Display(Name = "學(xué)校編碼")]
        [Required(ErrorMessage = "{0}是必填項(xiàng)")]
        [RegularExpression("^[0-9]{3,3}$", ErrorMessage = "{0}必須是3位數(shù)字")]
        [StringLength(3)]
        public string SchoolCode { get; set; }
        [Display(Name = "學(xué)校名稱")]
        [StringLength(50, ErrorMessage = "{0}最多輸入{1}個(gè)字符")]
        [Required(ErrorMessage = "{0}是必填項(xiàng)")]
        public string SchoolName { get; set; }
        [Display(Name = "學(xué)校類型")]
        [Required(ErrorMessage = "{0}是必填項(xiàng)")]
        public SchoolTypeEnum? SchoolType { get; set; }
        [Display(Name = "備注")]
        public string Remark { get; set; }
    }
    public class Major : BasePoco
    {
        [Display(Name = "專業(yè)編碼")]
        [Required(ErrorMessage = "{0}是必填項(xiàng)")]
        [RegularExpression("^[0-9]{3,3}$", ErrorMessage = "{0}必須是3位數(shù)字")]
        public string MajorCode { get; set; }
        [Display(Name = "專業(yè)名稱")]
        [StringLength(50, ErrorMessage = "{0}最多輸入{1}個(gè)字符")]
        [Required(ErrorMessage = "{0}是必填項(xiàng)")]
        public string MajorName { get; set; }
        [Display(Name = "備注")]
        public string Remark { get; set; }
        [Display(Name = "所屬學(xué)校")]
        [Required()]
        public Guid? SchoolId { get; set; }
        [Display(Name = "所屬學(xué)校")]
        public School School { get; set; }
        [Display(Name = "學(xué)生")]
        public List<StudentMajor> StudentMajors { get; set; }
    }
    public class Student : BasePoco
    {
        [Display(Name = "賬號(hào)")]
        [Required(ErrorMessage = "{0}是必填項(xiàng)")]
        [StringLength(50, ErrorMessage = "{0}最多輸入{1}個(gè)字符")]
        public string LoginName { get; set; }
        [Display(Name = "密碼")]
        [Required(AllowEmptyStrings = false)]
        [StringLength(32)]
        public string Password { get; set; }
        [Display(Name = "姓名")]
        [Required(ErrorMessage = "{0}是必填項(xiàng)")]
        [StringLength(50, ErrorMessage = "{0}最多輸入{1}個(gè)字符")]
        public string Name { get; set; }
        [Display(Name = "手機(jī)")]
        [RegularExpression("^[1][3,4,5,7,8][0-9]{9}$", ErrorMessage = "{0}格式錯(cuò)誤")]
        public string CellPhone { get; set; }
        [Display(Name = "郵編")]
        [RegularExpression("^[0-9]{6,6}$", ErrorMessage = "{0}必須是6位數(shù)字")]
        public string ZipCode { get; set; }
        [Display(Name = "日期")]
        public DateTime? EnRollDate { get; set; }
        [Display(Name = "專業(yè)")]
        public List<StudentMajor> StudentMajor { get; set; }
    }
    [MiddleTable]
    public class StudentMajor : BasePoco
    {
        public Major Major { get; set; }
        public Student Student { get; set; }
        public Guid MajorId { get; set; }
        public Guid StudentId { get; set; }
    }
}