在 Linux 上使用 SQLite DB 部署 ASP.Net Core API 后出现“没有这样的表”答案

【问题标题】：'No such table' after Deploying ASP.Net Core API with SQLite DB on Linux在 Linux 上使用 SQLite DB 部署 ASP.Net Core API 后出现“没有这样的表”
【发布时间】：2023-03-21 06:43:01
【问题描述】：

更新：我能够在根路径中找到measurements.db 文件。它没有像错误消息所说的那样有一个测量表，这可能会导致它。

用我的本地文件替换它 - 修复它并且程序按预期工作。

所以我的问题发生了变化：为什么它不在 db 文件中创建测量表？

你好，

首先项目在本地运行良好！我遇到的问题是，在发布后（使用命令dotnet publish -c Release -r debian-x64），将发布文件夹的文件移动到 Linux VM 并使用dotnet MessdatenController.ddl 启动它无法自行创建measurements.db 文件，这很可能导致以下错误。（手动添加/上传时也找不到它）。

info: Microsoft.Hosting.Lifetime[0]
      Now listening on: http://localhost:5000
info: Microsoft.Hosting.Lifetime[0]
      Now listening on: https://localhost:5001
info: Microsoft.Hosting.Lifetime[0]
      Application started. Press Ctrl+C to shut down.
info: Microsoft.Hosting.Lifetime[0]
      Hosting environment: Production
info: Microsoft.Hosting.Lifetime[0]
      Content root path: /
info: Microsoft.AspNetCore.Hosting.Diagnostics[1]
      Request starting HTTP/1.1 GET http://IP.OF.LINUX.VM/api/Measurements/GetMeasurements
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[0]
      Executing endpoint 'MessdatenController.Controllers.MeasurementsController.GetMeasurements (MessdatenController)'
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[3]
      Route matched with {action = "GetMeasurements", controller = "Measurements"}. Executing controller action with signature Microsoft.AspNetCore.Mvc.ActionResult`1[System.Collections.Generic.IEnumerable`1[MessdatenController.Models.Measurement]] GetMeasurements() on controller MessdatenController.Controllers.MeasurementsController (MessdatenController).
info: Microsoft.EntityFrameworkCore.Infrastructure[10403]
      Entity Framework Core 3.1.9 initialized 'MeasurementsContext' using provider 'Microsoft.EntityFrameworkCore.Sqlite' with options: None
fail: Microsoft.EntityFrameworkCore.Database.Command[20102]
      Failed executing DbCommand (21ms) [Parameters=[], CommandType='Text', CommandTimeout='30']
      SELECT "m"."MeasurementId", "m"."PM10", "m"."PM25", "m"."Posted", "m"."Timestamp"
      FROM "Measurements" AS "m"
      ORDER BY "m"."Timestamp"
fail: Microsoft.EntityFrameworkCore.Query[10100]
      An exception occurred while iterating over the results of a query for context type 'MessdatenController.Business.MeasurementsContext'.
      Microsoft.Data.Sqlite.SqliteException (0x80004005): SQLite Error 1: 'no such table: Measurements'.
         at Microsoft.Data.Sqlite.SqliteException.ThrowExceptionForRC(Int32 rc, sqlite3 db)
         at Microsoft.Data.Sqlite.SqliteCommand.PrepareAndEnumerateStatements(Stopwatch timer)+MoveNext()
         at Microsoft.Data.Sqlite.SqliteCommand.GetStatements(Stopwatch timer)+MoveNext()
         at Microsoft.Data.Sqlite.SqliteDataReader.NextResult()
         at Microsoft.Data.Sqlite.SqliteCommand.ExecuteReader(CommandBehavior behavior)
         at Microsoft.Data.Sqlite.SqliteCommand.ExecuteDbDataReader(CommandBehavior behavior)
         at System.Data.Common.DbCommand.ExecuteReader()
         at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteReader(RelationalCommandParameterObject parameterObject)
         at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.InitializeReader(DbContext _, Boolean result)
         at Microsoft.EntityFrameworkCore.Storage.Internal.NoopExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
         at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.MoveNext()
Microsoft.Data.Sqlite.SqliteException (0x80004005): SQLite Error 1: 'no such table: Measurements'.
   at Microsoft.Data.Sqlite.SqliteException.ThrowExceptionForRC(Int32 rc, sqlite3 db)
   at Microsoft.Data.Sqlite.SqliteCommand.PrepareAndEnumerateStatements(Stopwatch timer)+MoveNext()
   at Microsoft.Data.Sqlite.SqliteCommand.GetStatements(Stopwatch timer)+MoveNext()
   at Microsoft.Data.Sqlite.SqliteDataReader.NextResult()
   at Microsoft.Data.Sqlite.SqliteCommand.ExecuteReader(CommandBehavior behavior)
   at Microsoft.Data.Sqlite.SqliteCommand.ExecuteDbDataReader(CommandBehavior behavior)
   at System.Data.Common.DbCommand.ExecuteReader()
   at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteReader(RelationalCommandParameterObject parameterObject)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.InitializeReader(DbContext _, Boolean result)
   at Microsoft.EntityFrameworkCore.Storage.Internal.NoopExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.MoveNext()
info: Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker[2]
      Executed action MessdatenController.Controllers.MeasurementsController.GetMeasurements (MessdatenController) in 1061.5466ms
info: Microsoft.AspNetCore.Routing.EndpointMiddleware[1]
      Executed endpoint 'MessdatenController.Controllers.MeasurementsController.GetMeasurements (MessdatenController)'
fail: Microsoft.AspNetCore.Server.Kestrel[13]
      Connection id "0HM4PTAT76L67", Request id "0HM4PTAT76L67:00000001": An unhandled exception was thrown by the application.
Microsoft.Data.Sqlite.SqliteException (0x80004005): SQLite Error 1: 'no such table: Measurements'.
   at Microsoft.Data.Sqlite.SqliteException.ThrowExceptionForRC(Int32 rc, sqlite3 db)
   at Microsoft.Data.Sqlite.SqliteCommand.PrepareAndEnumerateStatements(Stopwatch timer)+MoveNext()
   at Microsoft.Data.Sqlite.SqliteCommand.GetStatements(Stopwatch timer)+MoveNext()
   at Microsoft.Data.Sqlite.SqliteDataReader.NextResult()
   at Microsoft.Data.Sqlite.SqliteCommand.ExecuteReader(CommandBehavior behavior)
   at Microsoft.Data.Sqlite.SqliteCommand.ExecuteDbDataReader(CommandBehavior behavior)
   at System.Data.Common.DbCommand.ExecuteReader()
   at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteReader(RelationalCommandParameterObject parameterObject)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.InitializeReader(DbContext _, Boolean result)
   at Microsoft.EntityFrameworkCore.Storage.Internal.NoopExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
   at Microsoft.EntityFrameworkCore.Query.Internal.QueryingEnumerable`1.Enumerator.MoveNext()
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at MessdatenController.Controllers.MeasurementsController.GetMeasurements() in C:\Users\michu\Desktop\Wissenschaftspreis-2021\MessdatenController\MessdatenController\Controllers\MeasurementsController.cs:line 23
   at lambda_method(Closure , Object , Object[] )
   at Microsoft.Extensions.Internal.ObjectMethodExecutor.Execute(Object target, Object[] parameters)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.SyncObjectResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeActionMethodAsync()
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeNextActionFilterAsync()
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeInnerFilterAsync()
--- End of stack trace from previous location where exception was thrown ---
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeFilterPipelineAsync>g__Awaited|19_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)
   at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)
   at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)
   at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.ProcessRequests[TContext](IHttpApplication`1 application)
info: Microsoft.AspNetCore.Hosting.Diagnostics[2]
      Request finished in 1312.107ms 500

通过 Apache 的路由应该可以正常工作，因为如果到达控制器方法。

现在关于我的文件：

Program.cs 保持默认。

Startup.cs

public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddDbContext<MeasurementsContext>(options => options.UseSqlite("Data Source=measurements.db"));

            services.AddTransient<IMeasurementsService, MeasurementsService>();

            services.AddControllers();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
    
            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });
        }
    }

Measurement.cs

public class Measurement
    {
        public Measurement(PostMeasurement pm, DateTime posted)
        {
            this.Timestamp = pm.Timestamp;
            this.PM10 = pm.PM10;
            this.PM25 = pm.PM25;
            this.Posted = posted;
        }

        public Measurement(Guid measurementId, DateTime timestamp, double pM10, double pM25, DateTime posted)
        {
            MeasurementId = measurementId;
            Timestamp = timestamp;
            PM10 = pM10;
            PM25 = pM25;
            Posted = posted;
        }

        public Guid MeasurementId { get; set; }

        public DateTime Timestamp { get; set; }

        public Double PM10 { get; set; }

        public Double PM25 { get; set; }

        public DateTime Posted { get; set; }
    }

MeasurementsContext.cs：

public class MeasurementsContext : DbContext
    {
        public MeasurementsContext(DbContextOptions<MeasurementsContext> options) : base(options)
        { }
        public DbSet<Measurement> Measurements { get; set; }
    }
}

服务

public interface IMeasurementsService
    {
        public Measurement AddMeasurement(PostMeasurement measurement, DateTime posted);
        public ICollection<Measurement> AddMeasurements(IEnumerable<PostMeasurement> measurements, DateTime posted);
        public IQueryable<Measurement> GetAllMeasurements();
        public IQueryable<Measurement> GetMeasurementsBetweenTimestamps(DateTime start, DateTime end);
    }

它的实现

public class MeasurementsService : IMeasurementsService
    {
        private readonly MeasurementsContext _context;

        public MeasurementsService(MeasurementsContext context)
        {
            _context = context;
        }

        public Measurement AddMeasurement(PostMeasurement measurement, DateTime posted)
        {
            Measurement m = new Measurement(measurement, posted);
            _context.Add(m);
            _context.SaveChanges();

            return m;
        }

        public ICollection<Measurement> AddMeasurements(IEnumerable<PostMeasurement> measurements, DateTime posted)
        {
            List<Measurement> result = new List<Measurement>();

            foreach (PostMeasurement postM in measurements)
            {
                Measurement tempM = new Measurement(postM, posted);
                _context.Add(tempM);
                result.Add(tempM);
            }
            _context.SaveChanges();

            return result;
        }

        public IQueryable<Measurement> GetAllMeasurements()
        {
            return _context.Measurements.OrderBy(m => m.Timestamp);
        }

        public IQueryable<Measurement> GetMeasurementsBetweenTimestamps(DateTime start, DateTime end)
        {
            return _context.Measurements.Where(r => r.Timestamp > start && r.Timestamp < end).OrderBy(m => m.Timestamp);
        }

    }

在查看我的问题时，我省略了控制器，因为它不应该很重要。

感谢您的任何建议，并随时问我任何问题 - 我会尽快回复

【问题讨论】：

标签： c# sqlite api asp.net-core deployment

【解决方案1】：

EntityFramework 的 SQLite 提供程序不会自动为您创建数据库或添加缺失的表。如果数据库文件不存在，您可以调用dbContext.Database.EnsureCreatedAsync() 让EF 创建数据库文件。然后它还将创建所有必需的表。但是，如果文件已经存在，则不会对其进行修改。

如果您以后想在数据库中添加其他表，您应该考虑使用migrations，它允许您随着时间的推移演变您的数据库架构，同时提供从旧版本数据库迁移到当前架构的方法.

如果您设置了迁移，则可以致电 dbContext.Database.EnsureMigratedAsync() 将待处理的迁移应用到数据库，并确保数据库与您期望的模型匹配。

您还可以使用dotnet ef command line utility 创建数据库或应用迁移。

【讨论】：

谢谢 - 这实际上解释得很好。我实际上已经在使用迁移，我会看看你的建议。