C#•6mo ago

Database suffix builder

Question, is doing something like this acceptable?

    public class EditorDbContext : DbContext
    {
        private readonly string _tableSuffix;

        public DbSet<EditorItem> EditorItems { get; set; }

        public EditorDbContext(DbContextOptions<EditorDbContext> options, string tableSuffix)
            : base(options)
        {
            _tableSuffix = tableSuffix ?? throw new ArgumentNullException(nameof(tableSuffix));
        }

        protected override void OnModelCreating(ModelBuilder builder)
        {
            builder.ApplyConfiguration(new EditorItemConfiguration(_tableSuffix));
        }
    }

    public class EditorDbContext : DbContext
    {
        private readonly string _tableSuffix;

        public DbSet<EditorItem> EditorItems { get; set; }

        public EditorDbContext(DbContextOptions<EditorDbContext> options, string tableSuffix)
            : base(options)
        {
            _tableSuffix = tableSuffix ?? throw new ArgumentNullException(nameof(tableSuffix));
        }

        protected override void OnModelCreating(ModelBuilder builder)
        {
            builder.ApplyConfiguration(new EditorItemConfiguration(_tableSuffix));
        }
    }

 public class EditorItemConfiguration : IEntityTypeConfiguration<EditorItem>
 {
     private string _suffix;
     public EditorItemConfiguration(string suffix)
     {
         _suffix = suffix;
     }
     public void Configure(EntityTypeBuilder<EditorItem> builder)
     {
         builder.ToTable($"tblplantekstobjects{_suffix}");
     }
 }

 public class EditorItemConfiguration : IEntityTypeConfiguration<EditorItem>
 {
     private string _suffix;
     public EditorItemConfiguration(string suffix)
     {
         _suffix = suffix;
     }
     public void Configure(EntityTypeBuilder<EditorItem> builder)
     {
         builder.ToTable($"tblplantekstobjects{_suffix}");
     }
 }

Though I think is is right I'm still getting some dependency injection problems but im not sure if i should spend time on fixing those or if there is a different way For example this:

 public async Task<List<EditorItemDto>> GetEditorTree(int regelingId)
 {
     string tableSuffix = "3";
     using (var dbContext = _dbContextFactory.CreateDbContext(tableSuffix))
     {
         var items = await dbContext.EditorItems.ToListAsync();
         Console.WriteLine($"Entities from EditorItem_{tableSuffix}: {items.Count}");
         var list = _mapper.Map<List<EditorItemDto>>(items);
         return list;
     }
 }

 public async Task<List<EditorItemDto>> GetEditorTree(int regelingId)
 {
     string tableSuffix = "3";
     using (var dbContext = _dbContextFactory.CreateDbContext(tableSuffix))
     {
         var items = await dbContext.EditorItems.ToListAsync();
         Console.WriteLine($"Entities from EditorItem_{tableSuffix}: {items.Count}");
         var list = _mapper.Map<List<EditorItemDto>>(items);
         return list;
     }
 }

18 Replies

Rowin ツOP•6mo ago

    public interface IEditorDbContextFactory
    {
        EditorDbContext CreateDbContext(string tableSuffix);

    }

    public interface IEditorDbContextFactory
    {
        EditorDbContext CreateDbContext(string tableSuffix);

    }

    public class EditorDbContextFactory : IEditorDbContextFactory
    {
        private readonly DbContextOptions<EditorDbContext> _options;

        public EditorDbContextFactory(DbContextOptions<EditorDbContext> options)
        {
            _options = options;
        }

        public EditorDbContext CreateDbContext(string tableSuffix)
        {
            return new EditorDbContext(_options, tableSuffix);
        }
    }

    public class EditorDbContextFactory : IEditorDbContextFactory
    {
        private readonly DbContextOptions<EditorDbContext> _options;

        public EditorDbContextFactory(DbContextOptions<EditorDbContext> options)
        {
            _options = options;
        }

        public EditorDbContext CreateDbContext(string tableSuffix)
        {
            return new EditorDbContext(_options, tableSuffix);
        }
    }

Angius•6mo ago

Why tho

Rowin ツOP•6mo ago

What do you mean?

Angius•6mo ago

Why do those tables even have suffixes

Rowin ツOP•6mo ago

Because our company said so

Angius•6mo ago

Ah, rip

Rowin ツOP•6mo ago

Yup

Angius•6mo ago

Well, in any case, it seems fine to me

Rowin ツOP•6mo ago

Same, yet

InvalidOperationException: Error while validating the service descriptor 'ServiceType: EditorApi.DbContexts.EditorDbContext Lifetime: Scoped ImplementationType: EditorApi.DbContexts.EditorDbContext': Unable to resolve service for type 'System.String' while attempting to activate 'EditorApi.DbContexts.EditorDbContext'.

InvalidOperationException: Error while validating the service descriptor 'ServiceType: EditorApi.DbContexts.EditorDbContext Lifetime: Scoped ImplementationType: EditorApi.DbContexts.EditorDbContext': Unable to resolve service for type 'System.String' while attempting to activate 'EditorApi.DbContexts.EditorDbContext'.

Angius•6mo ago

I guess it's trying to do constructor injection somewhere, where you pass the suffix to a constructor Seems like what you're doing is adding a prefix to all tables, rather than suffix, right? Like, tblplantekstobjectsUsers, tblplantekstobjectsBlogposts, etc?

Rowin ツOP•6mo ago

i though that was a suffix but yeah that is the case

Angius•6mo ago

https://stackoverflow.com/a/12967044/6042255 prefix_foo_suffix Seems you should be able to just use a convention

Rowin ツOP•6mo ago

I need need a new context every call with supplied prefix

FusedQyou•6mo ago

What is acceptable? Assigning default suffixes to tables? Why not? Only thing I don't like here is how you inject a primitive type into DI. You should probably have an actual configuration object

Rowin ツOP•6mo ago

What do you mean exactly?

FusedQyou•6mo ago

Well not DI directly, but as a parameter I would make an actual Configuration object instead I would also really consider using actual DI to get the context. I assume this is an API? You can just call AddDBContext and not use factories because there's no reason to Then you are forced to have a Configuration object 😎

Rowin ツOP•6mo ago

    public EditorDbContext(DbContextOptions<EditorDbContext> options, EditorDbContextConfig config)
        : base(options)
    {
        _tablePrefix = config.TablePrefix ?? throw new ArgumentNullException(nameof(config.TablePrefix));
    }

    public EditorDbContext(DbContextOptions<EditorDbContext> options, EditorDbContextConfig config)
        : base(options)
    {
        _tablePrefix = config.TablePrefix ?? throw new ArgumentNullException(nameof(config.TablePrefix));
    }

You mean something like this? god i keep using suffix but that should be prefix

FusedQyou•6mo ago

Yeah pretty much

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Database suffix builder