Loop/reflect through all properties in all EF Models to set Column Type

Question

My client has a standard of storing SQL Server decimals with a decimal(13,4) specification. As a result, in a very large and still-growing schema, I have nearly a hundred statements like these:

builder.Entity<MyObject>()
    .Property(x => x.MyField1)
    .ForSqlServerHasColumnType("decimal(13,4)");
builder.Entity<MyObject>()
    .Property(x => x.MyField2)
    .ForSqlServerHasColumnType("decimal(13,4)");
builder.Entity<MyObject2>()
    .Property(x => x.MyField1)
    .ForSqlServerHasColumnType("decimal(13,4)");

If there is a feature where I can tell EF directly that all decimals should be decimal(13,4) by default, I would like to use that. If not, can I use reflection to loop through every object/property in the model so I can do this in a couple statements?

Something like:

foreach(var efObj in EntityFrameWorkObjects)
{
    foreach (var objProperty in efObj)
    {
        if (objProperty is decimal || objProperty is decimal?)
        {
            builder.Entity<efObj>()
                .Property(x => x.efObj)
                .ForSqlServerHasColumnType("decimal(13,4)");
        }
    }
}

Reflection seems like a great way to go, because then I can implement some of our other conventions where, if an object has a Name and Description, the Name is required and limited to 256 chars.

Update: I followed the link in Ivan's comment and adapted it to this, which works for me:

foreach (var p in builder.Model
    .GetEntityTypes()
    .SelectMany(t => t.GetProperties())
    .Where(p => 
        p.ClrType == typeof(decimal) ||
        p.ClrType == typeof(decimal?)))
{
    p.SqlServer().ColumnType = "decimal(13,4)";
}

Soon after, he provided a full answer, which I changed slightly to work with both decimal and nullable decimal:

foreach (var pb in builder.Model
    .GetEntityTypes()
    .SelectMany(t => t.GetProperties())
    .Where(p => 
        p.ClrType == typeof(decimal) ||
        p.ClrType == typeof(decimal?))
    .Select(p => 
        builder.Entity(p.DeclaringEntityType.ClrType)
            .Property(p.Name)))
{
    pb.ForSqlServerHasColumnType("decimal(13,4)");
}

Both approaches work!

Update 2: I had to have my objects declared as DbSet<> in the context for the above to work. This didn't seem to be required when I was setting properties line by line.

Answer 1

In EF Core v1.1.0 you can use something like this:

foreach (var pb in modelBuilder.Model
    .GetEntityTypes()
    .SelectMany(t => t.GetProperties())
    .Where(p => p.ClrType == typeof(decimal) || p.ClrType == typeof(decimal?))
    .Select(p => modelBuilder.Entity(p.DeclaringEntityType.ClrType).Property(p.Name)))
{
    pb.ForSqlServerHasColumnType("decimal(13,4)");
}

Update (EF Core 2.x): Starting from EF Core 2.0, the model is built separately for each database provider, so HasAbcXyz methods are replaced with common HasXyz. The updated code (which also skips the explicitly configured properties) looks like this:

foreach (var property in modelBuilder.Model.GetEntityTypes()
    .SelectMany(t => t.GetProperties())
    .Where(p => p.ClrType == typeof(decimal) || p.ClrType == typeof(decimal?)))
{
    if (property.Relational().ColumnType == null)
        property.Relational().ColumnType = "decimal(13,4)";
}

Update (EF Core 3.x): With EF Core 3.0 metadata API changes (Relational() extensions removed, properties replaced with Get / Set method pair), the code is as follows:

foreach (var property in modelBuilder.Model.GetEntityTypes()
    .SelectMany(t => t.GetProperties())
    .Where(p => p.ClrType == typeof(decimal) || p.ClrType == typeof(decimal?)))
{
    if (property.GetColumnType() == null)
        property.SetColumnType("decimal(13,4)");
}

Update (Entity Framework Core 6): EF Core 6 includes convention model configuration that can be used to achieve this to all types. The advantage over looping through entities manually, is that this conventions already ignore certain types (like Ignore(), or properties that have Converters).

public class SomeDbContext : DbContext
{
    protected override void ConfigureConventions(
        ModelConfigurationBuilder configurationBuilder)
    {
        configurationBuilder
                .Properties<decimal>()
                .HavePrecision(19, 4);
    }
}

Answer 2

EF Core 6.0

It's now simple to configure defaults for every decimal property (or string, etc.):

protected override void ConfigureConventions(ModelConfigurationBuilder configurationBuilder)
{
    configurationBuilder
        .Properties<decimal>()
        .HavePrecision(19, 4);
}

More info: pre-convention model configuration

Answer 3

The approach mentioned above does not work when I'm working on EFCore 5.0.1 DB-First. The method below on MS document works:

[Column(TypeName = "decimal(18, 4)")]
public decimal Numeric { get; set; }