将日期时间从 C# 插入到 SqlSrv

Question

I need to save in the database a date field type "datetime" from C# using EntityFramework.

In MySql works fine but no in Sqlsrv.

The idea is that the system can work with MySql or SqlSrv, that's why I use datetime and not datetime2.

My model:

public partial class Entity: ITimeStamp
{
    
    public long Id { get; set; }
    public string Name { get; set; }
    public DateTime CreatedAt { get; set; }
    public DateTime UpdatedAt { get; set; }
}

My DbContext:

protected override void OnModelCreating(ModelBuilder modelBuilder) {
.......
        modelBuilder.Entity<Entity>(entity =>
        {
            entity.ToTable("entities");

            entity.HasIndex(e => e.Name, "entities_name_unique")
                .IsUnique();

            entity.Property(e => e.Id)
                .HasColumnType("int")
                .HasColumnName("id").ValueGeneratedOnAdd();

            entity.Property(e => e.CreatedAt)
                .HasColumnType("datetime")
                .HasColumnName("created_at");

            entity.Property(e => e.Name)
                .IsRequired()
                .HasColumnType("varchar(255)")
                .HasColumnName("name");

            entity.Property(e => e.UpdatedAt)
                .HasColumnType("datetime")
                .HasColumnName("updated_at");
        });
......
}
public override int SaveChanges()
    {
        var entries = ChangeTracker
            .Entries()
            .Where(e => e.Entity is ITimeStamp && (
                e.State is EntityState.Added or EntityState.Modified));

        foreach (var entityEntry in entries)
        {
            ((ITimeStamp)entityEntry.Entity).UpdatedAt = DateTime.Now;

            if (entityEntry.State == EntityState.Added)
            {
                ((ITimeStamp)entityEntry.Entity).CreatedAt = DateTime.Now;
            }
        }

        return base.SaveChanges();
    }

My Controller:

var entity = new Entity
{
    Name = installer.CompanyName,
    ...
};
_context.Entities.Add(entity);
await _context.SaveChangesAsync();

Exception:

System.Data.SqlTypes.SqlTypeException: SqlDateTime overflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM.
   at Microsoft.Data.SqlClient.SqlCommand.<>c.<ExecuteDbDataReaderAsync>b__169_0(Task`1 result)
   at System.Threading.Tasks.ContinuationResultTaskFromResultTask`2.InnerInvoke()
   at System.Threading.Tasks.Task.<>c.<.cctor>b__277_0(Object obj)
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
--- End of stack trace from previous location ---
   at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state)
   at System.Threading.Tasks.Task.ExecuteWithThreadLocal(Task& currentTaskSlot, Thread threadPoolThread)
--- End of stack trace from previous location ---
   at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteReaderAsync(RelationalCommandParameterObject parameterObject, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteReaderAsync(RelationalCommandParameterObject parameterObject, CancellationToken cancellationToken)
   at Microsoft.EntityFrameworkCore.Update.ReaderModificationCommandBatch.ExecuteAsync(IRelationalConnection connection, CancellationToken cancellationToken)

I tried setting the fields to nullable, but instead of throwing an exception it doesn't save any date.

Answer 1

The problem is that the default value for a DateTime instance in .NET is 0001-01-01T00:00:00 (ISO8601 notation). In Sql Server the range of a DateTime is limited and must be greater than 1753-1-1T00:00:00 (also ISO8601 notation). You must specify a value of your DateTime instance that is greater than this date.

An alternative is to use a Nullable DateTime? instance and make the column value accept nulls in your DB schema so that a lack of value results in a NULL value in the database.

If you are sure that you are setting the values correctly before the save you should profile the operation using Sql Profiler and see what the value is that is being passed and causing the Exception. It could be that the name of the column does not correspond with the name of the schema column or that there is another column in the database that is not mapped back to your entity.

Answer 2

I do something similar in my projects. Below is the code I have and it is working perfectly fine in over 10 projects. Below is my DbContext

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

    //This allows the audit fields to automatically be added, or updated.
    public override int SaveChanges()
    {

        var state = this.ChangeTracker.Entries().Select(x => x.State).ToList();

        state.ForEach(x => {

            switch(x)
            {
                case EntityState.Added:
                    UpdateAddedEntity();
                    break;
                case EntityState.Modified:
                    UpdateModifiedEntity();
                    break;
            }

        });

        return base.SaveChanges();
    }

    //Update Entity Pattern
    protected void UpdateAddedEntity()
    {
        var created = this.ChangeTracker.Entries().Where(e => e.State == EntityState.Added).Select(e => e.Entity).ToArray();

        foreach (var entity in created)
        {
            if (entity is AuditFields)
            {
                var auditFields = entity as AuditFields;
                auditFields.CreateDateTimeUtc = DateTime.UtcNow;
                auditFields.ModifiedDateTimeUtc = DateTime.UtcNow;
                auditFields.Active = true;
            }
        }
    }

    protected void UpdateModifiedEntity()
    {
        //Modified record changes
        var modified = this.ChangeTracker.Entries().Where(e => e.State == EntityState.Modified).Select(e => e.Entity).ToArray();

        foreach (var entity in modified)
        {
            if (entity is AuditFields)
            {
                var auditFields = entity as AuditFields;
                auditFields.ModifiedDateTimeUtc = DateTime.UtcNow;
            }
        }
    }

Oh I guess if you want the model for my audit fields here that is too:

public class AuditFields
    {
        protected AuditFields()
        {
            Active = true;
            CreateDateTimeUtc = DateTime.UtcNow;
            ModifiedDateTimeUtc = DateTime.UtcNow;
        }

        [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public Guid Id { get; set; }

        [Required]
        [IndexColumn]
        public DateTime CreateDateTimeUtc { get; set; }

        [Required]
        [IndexColumn]
        public DateTime ModifiedDateTimeUtc { get; set; }

        [IndexColumn]
        public bool Active { get; set; }
    }

Answer 3

After many test, finally I solve my problem.

I remove the datetime definition from DBContext and leave it in the model definition, so that EF decides which type of datetime to choose for the DB type chosen by the client.