Добавил ограничение поля в БД

Payments/Payment.WebApi/Infrastructures/Databases/MapConfigurations/UserBalanceDbMap.cs

+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+using Payment.WebApi.Models.DbModels;
+
+namespace Payment.WebApi.Infrastructures.Databases.MapConfigurations;
+
+public class UserBalanceDbMap : IEntityTypeConfiguration<UserBalance>
+{
+    public void Configure(EntityTypeBuilder<UserBalance> builder)
+    {
+        builder.HasKey(opt => opt.Id);
+        builder.Property(opt => opt.Currency).HasMaxLength(8).IsRequired();
+        builder.Property(opt => opt.Amount).HasColumnType("NUMERIC(18,2)");
+    }
+}
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Payments/Payment.WebApi/Infrastructures/Databases/MapConfigurations/UserDbMap.cs

+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+using Payment.WebApi.Models.DbModels;
+
+namespace Payment.WebApi.Infrastructures.Databases.MapConfigurations;
+
+public class UserDbMap : IEntityTypeConfiguration<User>
+{
+    public void Configure(EntityTypeBuilder<User> builder)
+    {
+        builder.HasKey(opt => opt.Id);
+        builder.Property(opt => opt.FirstName).HasColumnType("VARCHAR(256)").IsRequired();
+        builder.Property(opt => opt.LastName).HasColumnType("VARCHAR(256)");
+        builder.Property(opt => opt.MiddleName).HasColumnType("VARCHAR(256)");
+        builder.Property(opt => opt.Email).HasMaxLength(128).IsRequired();
+        builder.Property(opt => opt.Age).HasColumnType("SMALLINT");
+    }
+}
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Payments/Payment.WebApi/Infrastructures/Databases/PaymentDbContext.cs

 using Microsoft.EntityFrameworkCore;
+using Payment.WebApi.Infrastructures.Databases.MapConfigurations;
 using Payment.WebApi.Models.DbModels;
 
 namespace Payment.WebApi.Infrastructures.Databases;
@@ -24,5 +25,8 @@ public class PaymentDbContext : DbContext
         modelBuilder.SeedUser();
         modelBuilder.SeedSupplier();
         modelBuilder.SeedUserBalance();
+
+        modelBuilder.ApplyConfiguration(new UserDbMap());
+        modelBuilder.ApplyConfiguration(new UserBalanceDbMap());
     }
 }
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