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本篇内容介绍了"用.NET生成数据库的方法步骤"的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧!希望大家仔细阅读，能够学有所成!

开篇语

本文主要是回顾下从项目创建到生成数据到数据库(代码优先)的全部过程。采用EFCore作为ORM框架。

本次示例环境：vs2019、net5、mysql

创建项目

本次事例代码是用过vs2019创建的ASP.NET Core Web API项目

可以通过可视化界面创建或者通过命令行创建

dotnet new webapi -o Net5ByDocker创建实体类

安装连接MySQL数据库组件

增加实体类

[Table("user")] public class User { public User() { Id = Guid.NewGuid().ToString(); } public User(string account, string password, string creater) : this() { Account = account; Password = password; Deleted = false; SetCreater(creater); } [Key] [Comment("主键")] [StringLength(36)] [Required] public string Id { get; private set; } [Comment("帐号")] [StringLength(36)] [Required] public string Account { get; private set; } [Comment("密码")] [StringLength(36)] [Required] public string Password { get; private set; } [Comment("余额")] [Column(TypeName = "decimal(18, 2)")] [Required] public decimal Money { get; set; } [Comment("是否删除")] [Column(TypeName = "tinyint(1)")] [Required] public bool Deleted { get; private set; } [Comment("创建人")] [StringLength(20)] [Required] public string Creater { get; private set; } [Comment("创建时间")] [Required] public DateTime CreateTime { get; private set; } [Comment("修改人")] [StringLength(20)] [Required] public string Modifyer { get; private set; } [Comment("修改时间")] [Required] public DateTime ModifyTime { get; private set; } public void SetCreater(string name) { Creater = name; CreateTime = DateTime.Now; SetModifyer(name); } public void SetModifyer(string name) { Modifyer = name; ModifyTime = DateTime.Now; } }

这种只是增加实体类类型的一种方式，可能这种看着比较乱，还可以通过OnModelCreating实现，详情看参考文档

增加数据库上下文OpenDbContext

public class OpenDbContext : DbContext { public OpenDbContext(DbContextOptions options) : base(options) { } public DbSet Users { get; set; } }

Startup注入连接数据库操作

var connection = Configuration["DbConfig:Mysql:ConnectionString"]; var migrationsAssembly = IntrospectionExtensions.GetTypeInfo(typeof(Startup)).Assembly.GetName().Name; services.AddDbContext(option => option.UseMySql(connection, ServerVersion.AutoDetect(connection), x => { x.UseNewtonsoftJson(); x.MigrationsAssembly(migrationsAssembly); }));生成迁移文件

引用组件

迁移命令

add-migration Init

结果

image.png

要看下生成的迁移文件是否是自己预期的那样子，也可以在这一步就生成数据库，命令：Update-Database

数据种子

增加OpenDbSend类，添加数据种子

public class OpenDbSend { /// /// 生成数据库以及数据种子 /// /// 数据库上下文 /// 日志 /// 重试次数 /// public static async Task SeedAsync(OpenDbContext dbContext, ILoggerFactory loggerFactory, int? retry = 0) { int retryForAvailability = retry.Value; try { dbContext.Database.Migrate();//如果当前数据库不存在按照当前 model 创建，如果存在则将数据库调整到和当前 model 匹配 await InitializeAsync(dbContext).ConfigureAwait(false); //if (dbContext.Database.EnsureCreated())//如果当前数据库不存在按照当前 model创建，如果存在则不管了。 // await InitializeAsync(dbContext).ConfigureAwait(false); } catch (Exception ex) { if (retryForAvailability

< 3) { retryForAvailability++; var log = loggerFactory.CreateLogger(); log.LogError(ex.Message); await SeedAsync(dbContext, loggerFactory, retryForAvailability).ConfigureAwait(false); } } } /// /// 初始化数据 /// /// /// public static async Task InitializeAsync(OpenDbContext context) { if (!context.Set().Any()) { await context.Set().AddAsync(new User("azrng", "123456", "azrng")).ConfigureAwait(false); await context.Set().AddAsync(new User("张三", "123456", "azrng")).ConfigureAwait(false); } await context.SaveChangesAsync().ConfigureAwait(false); } } 设置项目启动时候调用 public static async Task Main(string[] args) { var host = CreateHostBuilder(args).Build(); using (var scope = host.Services.CreateScope()) { var services = scope.ServiceProvider; var loggerFactory = services.GetRequiredService(); var _logger = loggerFactory.CreateLogger(); try { var openContext = services.GetRequiredService(); await OpenDbSend.SeedAsync(openContext, loggerFactory).ConfigureAwait(false); } catch (Exception ex) { _logger.LogError(ex, $"项目启动出错 {ex.Message}"); } } await host.RunAsync().ConfigureAwait(false); }生成数据库 启动项目，自动生成数据库 image.png 表结构如下 image.png 如果后期数据库字段或者结构有变动，可以再次生成迁移文件然后生成数据库 查询数据/// /// 用户接口 /// public interface IUserService { string GetName(); /// /// 查询用户信息 /// /// /// Task GetDetailsAsync(string account); } /// /// 用户实现 /// public class UserService : IUserService { private readonly OpenDbContext _dbContext; public UserService(OpenDbContext dbContext) { _dbContext = dbContext; } public string GetName() { return "AZRNG"; } /// public async Task GetDetailsAsync(string account) { return await _dbContext.Set().FirstOrDefaultAsync(t =>

t.Account == account).ConfigureAwait(false); } }

It is generally recommended to establish a specified return Model class, and then only query the required content, not directly return the entity class

controller method

//////Query user details/////// [HttpGet] public async Task GetDetailsAsync(string account) { return await _userService.GetDetailsAsync(account).ConfigureAwait(false); }

query results

{ "id": "e8976d0a-6ee9-4e2e-b8d8-1fe6e85b727b", "account": "azrng", "password": "123456", "money": 0, "deleted": false, "creater": "azrng", "createTime": "2021-05-09T15:48:45.730302", "modifyer": "azrng", "modifyTime": "2021-05- 09T15:48:45.730425" } The content of "Method steps of generating database with. NET" is introduced here. Thank you for reading. If you want to know more about industry-related knowledge, you can pay attention to the website. Xiaobian will output more high-quality practical articles for everyone!

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