Unable to insert after changing attribute type from int to decimal

This my DAC code
#endregion
#region QtyPlan
[PXDecimal]
[PXUIField(DisplayName = "Qty Plan", Required = true)]
public virtual Decimal? QtyPlan { get; set; }
public abstract class qtyPlan : PX.Data.BQL.BqlDecimal.Field<qtyPlan> { }
#endregion
Please Help Me