数据库架构在 Asp.net Core 2.2 和 Entity Framework Core 的运行时没有改变

Question

我有一个应用程序，其中数据保存在不同用户的不同 sql 模式中。

例如

用户 1 的数据保存在 SCHEMA1 中

用户 2 的数据保存在 SCHEMA2 中

以前的应用程序是在 MVC 3 中开发的，它运行良好且符合预期。 现在，我们正在迁移 .Net Core 2.2 中的应用程序，其中此功能不起作用
.net 核心没有IDbModelCacheKeyProvider，因为只有一个架构在工作

下面是 DBContext 文件

public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
    //public string Schema { get; set; }
    private readonly IConfiguration configuration;
    public string SchemaName { get; set; }

    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
        : base(options)
    {

    }

    public ApplicationDbContext(string schemaname)
        : base()
    {
        SchemaName = schemaname;
    }

    public DbSet<EmployeeDetail> EmployeeDetail { get; set; }



    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        var builder = new ConfigurationBuilder().SetBasePath(Directory.GetCurrentDirectory())
                      .AddJsonFile("appsettings.json");
        var configuration = builder.Build();

        optionsBuilder.UseSqlServer(configuration["ConnectionStrings:SchemaDBConnection"]);

        var serviceProvider = new ServiceCollection().AddEntityFrameworkSqlServer()
                            .AddTransient<IModelCustomizer, SchemaContextCustomize>()
                            .BuildServiceProvider();
    }


    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.RemovePluralizingTableNameConvention();
        modelBuilder.HasDefaultSchema(SchemaName);
        base.OnModelCreating(modelBuilder);
    }

    public string CacheKey
    {
        get { return SchemaName; }
    }


}   


public class SchemaContextCustomize : ModelCustomizer
{
    public SchemaContextCustomize(ModelCustomizerDependencies dependencies)
        : base(dependencies)
    {

    }
    public override void Customize(ModelBuilder modelBuilder, DbContext dbContext)
    {
        base.Customize(modelBuilder, dbContext);

        string schemaName = (dbContext as ApplicationDbContext).SchemaName;
        (dbContext as ApplicationDbContext).SchemaName = schemaName;

    }
}

我的问题是如何在运行时更改 schemaName

那么组织该机制的正确方法是什么：

通过用户凭据找出架构名称； 从特定架构的数据库中获取用户特定的数据。

Answer 1

我能够通过更改 onConfiguring 方法在运行时更改架构

    public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{

    public string SchemaName { get; set; }


    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
        : base(options)
    {

    }

    public ApplicationDbContext(string schemaname)
        : base()
    {
        SchemaName = schemaname;
    }

    public DbSet<EmployeeDetail> EmployeeDetail { get; set; }



    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {

        var builder = new ConfigurationBuilder().SetBasePath(Directory.GetCurrentDirectory())
                      .AddJsonFile("appsettings.json");
        var configuration = builder.Build();

        var serviceProvider = new ServiceCollection().AddEntityFrameworkSqlServer()
                            .AddSingleton<IModelCustomizer, SchemaContextCustomize>()
                            .BuildServiceProvider();
        optionsBuilder.UseSqlServer(configuration["ConnectionStrings:SchemaDBConnection"]).UseInternalServiceProvider(serviceProvider);
    }


    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
       // modelBuilder.MapProduct(SchemaName);

        modelBuilder.RemovePluralizingTableNameConvention();
        if (!string.IsNullOrEmpty(SchemaName))
        {
            modelBuilder.HasDefaultSchema(SchemaName);
        }
        base.OnModelCreating(modelBuilder);
    }

    public string CacheKey
    {
        get { return SchemaName; }
    }
public class SchemaContextCustomize : ModelCustomizer
{
    public SchemaContextCustomize(ModelCustomizerDependencies dependencies)
        : base(dependencies)
    {

    }
    public override void Customize(ModelBuilder modelBuilder, DbContext dbContext)
    {
        base.Customize(modelBuilder, dbContext);

        string schemaName = (dbContext as ApplicationDbContext).SchemaName;
        (dbContext as ApplicationDbContext).SchemaName = schemaName;

    }
}
}

Answer 2

最好的方法是使用多租户架构，以便能够为每个用户（租户）使用数据库架构
此架构推荐用于 Saas 应用程序

概念

让我们就一些基本概念达成一致：

• 我们使用租户识别（或解析）策略来找出我们正在与哪个租户交谈
• 租户 DbContext 访问策略将找出检索（和存储）的方式
  
  本文将向您展示如何使用 .net 核心实现多租户应用程序：https://stackify.com/writing-multitenant-asp-net-core-applications/