This is an example of a DAC Extension Table, linking to the Warehouse table in Acumatica.

ISPSMapadocInSiteExtension

    [Serializable]
    [PXCacheName("Warehouse Trading Partner")]
    [PXTable(typeof(INSite.siteID), IsOptional = true)]
    public class ISPSMapadocINSiteExtension : PXCacheExtension<INSite>
    {
        #region Siteid
        [PXDBInt(IsKey = true)]
        [PXUIField(DisplayName = "Siteid")]
        public virtual int? Siteid { get; set; }
        public abstract class siteid : PX.Data.BQL.BqlInt.Field<siteid> { }
        #endregion

        #region Spstp
        [PXDBBool()]
        [PXUIField(DisplayName = "EDI Warehouse")]
        public virtual bool? Spstp { get; set; }
        public abstract class spstp : PX.Data.BQL.BqlBool.Field<spstp> { }
        #endregion

        #region SPSLastModifiedDateTime
        [PXDBDate()]
        [PXUIField(DisplayName = "Last Modified Date Time")]
        public virtual DateTime? SPSLastModifiedDateTime { get; set; }
        public abstract class sPSLastModifiedDateTime : PX.Data.BQL.BqlDateTime.Field<sPSLastModifiedDateTime> { }
        #endregion
    }