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9.20 模型生成数据库

开始之前

Fur.Web.Entry 层需要安装 Microsoft.EntityFrameworkCore.Tools 包。

9.20.1 数据库开发方式

Furion 提供两种主要方法来 保持实体模型和数据库架构同步

至于我们应该选用哪个方法,请确定你是希望以实体模型为准还是以数据库为准:

  • 如果希望 以实体模型为准,请使用正向工程(Code First)。 对实体模型进行更改时,此方法会以增量方式将相应架构更改应用到数据库,以使数据库保持与实体模型兼容。

  • 如果希望 以数据库架构为准,请使用反向工程(Database First)。 使用此方法,可通过将数据库架构反向工程到实体模型来生成相应的实体类型。

本章节是 正向工程(Code First) 的相关内容。

9.20.2 操作指南

特别注意

Furion 框架默认数据迁移的程序集为:Furion.Database.Migrations,所以如果您改了程序集名称或通过 Nuget 方式安装的 Furion 包,则需要配置迁移程序集名称:

services.AddDatabaseAccessor(options =>{    options.AddDbPool<FurionDbContext>(DbProvider.Sqlite);}, "存放迁移文件的项目名称");

另外,如果应用中配置了多个数据库上下文,那么所有的 迁移命令 都需要指定 -Context 数据库上下文名称 参数。如:

Add-Migration v1.0.0 -Context FurionDbContext

9.20.2.1 创建实体模型 Person

using Furion.DatabaseAccessor;using System;using System.Collections.Generic;using System.ComponentModel.DataAnnotations;namespace Furion.Core{    public class Person : Entity    {        /// <summary>        /// 构造函数        /// </summary>        public Person()        {            CreatedTime = DateTime.Now;            IsDeleted = false;        }        /// <summary>        /// 姓名        /// </summary>        [MaxLength(32)]        public string Name { get; set; }        /// <summary>        /// 年龄        /// </summary>        public int Age { get; set; }        /// <summary>        /// 住址        /// </summary>        public string Address { get; set; }    }}
实体约定

所有数据库实体必须直接或间接继承 IEntity 接口。

9.20.2.2 打开 程序包管理控制台

9.20.2.3 切换默认项目

程序包管理控制台 默认项目设置为 Furion.Database.Migrations

9.20.2.4 创建模型版本

Add-Migration v1.0.0
特别说明

v1.0.0 是此处数据库更改的版本号,可以写任何字符串,但推荐写版本号,每次 +1

最终命令如下:

PM> Add-Migration v1.0.0Build started...Build succeeded.Microsoft.EntityFrameworkCore.Model.Validation[10400]      Sensitive data logging is enabled. Log entries and exception messages may include sensitive application data, this mode should only be enabled during development.Microsoft.EntityFrameworkCore.Infrastructure[10403]      Entity Framework Core 5.0.0-rc.1.20451.13 initialized 'FurionDbContext' using provider 'Microsoft.EntityFrameworkCore.Sqlite' with options: SensitiveDataLoggingEnabled DetailedErrorsEnabled MaxPoolSize=100 MigrationsAssembly=Furion.Database.MigrationsTo undo this action, use Remove-Migration.PM>

生成成功后,Furion.Database.Migrations 项目下会新增 Migrations 文件夹(如果没有),同时本次的架构生成文件,如:

9.20.2.5 更新到数据库

Update-Database

执行该命令后,数据库就会自动根据模型生成对应的表。

小知识

如果 Update-Database 后面带字符串参数,则会自动还原数据库到指定版本,如:

Update-Database v0.0.3

将数据库还原到 v0.0.3 版本

9.20.3 更新模型

如果模型改变了,重复上面操作即可,如:

Add-Migration v1.0.1
Update-Database

9.20.4 导出 Sql

有些时候,我们没有直接更新数据库的权限,或者怕出问题,我们都会先生成 Sql 看看,这时候只需要通过 Script-Migration 导出即可,如:

Script-Migration

9.20.5 VS Code/Rider/任何IDE/操作系统 方式

9.20.5.1 安装 dotnet ef

dotnet tool install --global dotnet-ef --version 5.0.0-rc.2.20475.6

9.20.5.2 cd 目录

通过 VS Code 打开 .sln 所在的目录,如:framework

之后进入 Furion.Database.Migrations 目录

cd Furion.Database.Migrations

9.20.5.3 执行命令

dotnet ef migrations add v1.0.0 -s "../Furion.Web.Entry"
dotnet ef database update -s "../Furion.Web.Entry"

9.20.6 应用启动时自动生成数据库

Furion 框架建议大家使用命令方式操作数据库,完全不推荐自动化生成数据库,但是有些特殊情况下,有这个必要,故将此功能写出:

9.20.6.1 对已经生成 Migrations 文件情况

如果已经生成 Migrations 文件,那么可以直接在 Startup.cs 代码中实现程序启动时自动执行 update-database 命令,如:

public void Configure(IApplicationBuilder app, IHostingEnvironment env){    // 判断开发环境!!!必须!!!!    if (env.IsDevelopment())    {        Scoped.Create((_, scope) =>        {            var context = scope.ServiceProvider.GetRequiredService<FurionDbContext>();            context.Database.Migrate();        });    }    // 其他代码}

9.20.6.2 如果没有生成过 Migrations 文件情况

public void Configure(IApplicationBuilder app, IHostingEnvironment env){    // 判断开发环境!!!必须!!!!    if (env.IsDevelopment())    {        Scoped.Create((_, scope) =>        {            var context = scope.ServiceProvider.GetRequiredService<FurionDbContext>();            context.Database.EnsureCreated();        });    }    // 其他代码}

如果需要在创建数据库之前先删除旧的,可先调用 context.Database.EnsureDeleted(); 代码。慎重!!!!!!!!!!!!

9.20.7 MySql.EntityFrameworkCore.NET 6.0.8+ 问题

.NET 6.0.8+ 版本,微软底层修改了 IDesignTimeServices 逻辑导致 MySql.EntityFrameworkCore 版本没有及时更新导致一下错误:

PM> Add-Migration v0.0.1Build started...Build succeeded.Microsoft.EntityFrameworkCore.Model.Validation[10400]      Sensitive data logging is enabled. Log entries and exception messages may include sensitive application data; this mode should only be enabled during development.Microsoft.EntityFrameworkCore.Infrastructure[10403]      Entity Framework Core 6.0.8 initialized 'DefaultDbContext' using provider 'MySql.EntityFrameworkCore:6.0.4+MySQL8.0.30' with options: SensitiveDataLoggingEnabled DetailedErrorsEnabled MaxPoolSize=100 MigrationsAssembly=Furion.TestMS.Database.Migrations System.InvalidOperationException: Unable to resolve service for type 'Microsoft.EntityFrameworkCore.Storage.TypeMappingSourceDependencies' while attempting to activate 'MySql.EntityFrameworkCore.Storage.Internal.MySQLTypeMappingSource'.   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateArgumentCallSites(Type implementationType, CallSiteChain callSiteChain, ParameterInfo[] parameters, Boolean throwIfCallSiteNotFound)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateConstructorCallSite(ResultCache lifetime, Type serviceType, Type implementationType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.TryCreateExact(ServiceDescriptor descriptor, Type serviceType, CallSiteChain callSiteChain, Int32 slot)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateCallSite(Type serviceType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.GetCallSite(Type serviceType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateArgumentCallSites(Type implementationType, CallSiteChain callSiteChain, ParameterInfo[] parameters, Boolean throwIfCallSiteNotFound)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateConstructorCallSite(ResultCache lifetime, Type serviceType, Type implementationType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.TryCreateExact(ServiceDescriptor descriptor, Type serviceType, CallSiteChain callSiteChain, Int32 slot)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateCallSite(Type serviceType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.GetCallSite(Type serviceType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateArgumentCallSites(Type implementationType, CallSiteChain callSiteChain, ParameterInfo[] parameters, Boolean throwIfCallSiteNotFound)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateConstructorCallSite(ResultCache lifetime, Type serviceType, Type implementationType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.TryCreateExact(ServiceDescriptor descriptor, Type serviceType, CallSiteChain callSiteChain, Int32 slot)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.TryCreateEnumerable(Type serviceType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateCallSite(Type serviceType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.GetCallSite(Type serviceType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateArgumentCallSites(Type implementationType, CallSiteChain callSiteChain, ParameterInfo[] parameters, Boolean throwIfCallSiteNotFound)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateConstructorCallSite(ResultCache lifetime, Type serviceType, Type implementationType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.TryCreateExact(ServiceDescriptor descriptor, Type serviceType, CallSiteChain callSiteChain, Int32 slot)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateCallSite(Type serviceType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.GetCallSite(Type serviceType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateArgumentCallSites(Type implementationType, CallSiteChain callSiteChain, ParameterInfo[] parameters, Boolean throwIfCallSiteNotFound)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateConstructorCallSite(ResultCache lifetime, Type serviceType, Type implementationType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.TryCreateExact(ServiceDescriptor descriptor, Type serviceType, CallSiteChain callSiteChain, Int32 slot)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateCallSite(Type serviceType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.GetCallSite(Type serviceType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateArgumentCallSites(Type implementationType, CallSiteChain callSiteChain, ParameterInfo[] parameters, Boolean throwIfCallSiteNotFound)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateConstructorCallSite(ResultCache lifetime, Type serviceType, Type implementationType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.TryCreateExact(ServiceDescriptor descriptor, Type serviceType, CallSiteChain callSiteChain, Int32 slot)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.CreateCallSite(Type serviceType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteFactory.GetCallSite(Type serviceType, CallSiteChain callSiteChain)   at Microsoft.Extensions.DependencyInjection.ServiceProvider.CreateServiceAccessor(Type serviceType)   at System.Collections.Concurrent.ConcurrentDictionary`2.GetOrAdd(TKey key, Func`2 valueFactory)   at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(Type serviceType, ServiceProviderEngineScope serviceProviderEngineScope)   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type serviceType)   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService(IServiceProvider provider, Type serviceType)   at Microsoft.Extensions.DependencyInjection.ServiceProviderServiceExtensions.GetRequiredService[T](IServiceProvider provider)   at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.AddMigration(String name, String outputDir, String contextType, String namespace)   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigrationImpl(String name, String outputDir, String contextType, String namespace)   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigration.<>c__DisplayClass0_0.<.ctor>b__0()   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass3_0`1.<Execute>b__0()   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)Unable to resolve service for type 'Microsoft.EntityFrameworkCore.Storage.TypeMappingSourceDependencies' while attempting to activate 'MySql.EntityFrameworkCore.Storage.Internal.MySQLTypeMappingSource'.PM> 

解决办法也很简单,只需要在启动层添加 MysqlEntityFrameworkDesignTimeServices.cs 并写入以下内容即可:

using Microsoft.EntityFrameworkCore.Design;using MySql.EntityFrameworkCore.Extensions;namespace YourProject.Web.Entry;public class MysqlEntityFrameworkDesignTimeServices : IDesignTimeServices{    public void ConfigureDesignTimeServices(IServiceCollection serviceCollection)    {        serviceCollection.AddEntityFrameworkMySQL();        new EntityFrameworkRelationalDesignServicesBuilder(serviceCollection)            .TryAddCoreServices();    }}

相关 Issue 讨论:https://gitee.com/dotnetchina/Furion/issues/I5O5ER

9.20.8 反馈与建议

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想了解更多 正向工厂 知识可查阅 EF Core - 管理数据库架构 章节。

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