What are Surrogate Keys and Natural Keys? Why to use them

The most important piece of the DAC is the KEY configuration.

A simple DAC should have an identity ID column which will auto-generate in SQL.

To make the key look nicer in the UI, specify a CD field which operates as the Substitute Key for the UI only.

Move the IsKey = true from the ID field to the CD field

The CD field will have a selector looking at itself

#region PlantID
[PXDBIdentity]
public virtual int? PlantID { get; set; }
public abstract class plantID : PX.Data.BQL.BqlInt.Field<plantID> { }
#endregion

#region PlantCD
[PXDBString(50, IsKey = true, IsUnicode = true, InputMask = ">aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa")]
[PXDefault]
[PXUIField(DisplayName = "Plant ID", Required = true)]
[PXSelector(typeof(Search<PlantsDAC.plantCD>),
typeof(PlantsDAC.plantCD))]
[AutoNumber(typeof(DSAPSetupExt.usrDSPositivePayNumberingSequenceID), typeof(AccessInfo.businessDate))]
public virtual string PlantCD { get; set; }
public abstract class plantCD : PX.Data.BQL.BqlString.Field<plantCD> { }
#endregion

NOTE: this also includes [AutoNumber] which may not be required in your situation.

When referencing the DAC from other tables (as a foreign key, use the ID field in the selector with the CD field specified as the Substitute Key:

#region ProductID
[PXDBInt(IsKey = true)]
[PXSelector(typeof(Search<ProductsDAC.productID>),
    typeof(ProductsDAC.productCD),
    SubstituteKey = typeof(ProductsDAC.productCD))]
[PXUIField(DisplayName = "Product ID")]
public virtual int? ProductID { get; set; }
public abstract class productID : PX.Data.BQL.BqlInt.Field<productID> { }
#endregion