【场景】link实体 源单信息字段讲解
背景：星空的关联关系是通过在数据包中的关联实体增加源单信息，而后通过标准保存操作将link信息转换为实际的关联关系和反写计算逻辑
【问题1】自定义单据怎么增加关联关系
a)下游单据增加单据关联实体配置，建议如果下游存在单据体字段跟上游关联，则把单据关联实体设置在单据体（按行关联源单）
下图为标准产品采购订单的单据关联实体配置
b)在转换规则中，配置转换类型为关联携带，在下游单据数据包生成的时候，平台会把信息填入到该实体中
【问题2】link表怎么查看对应的源单
0)数据准备，上游采购申请单下推采购订单，按照物料编码分录合并
1)生成的下游单据
2)数据库讲解
```sql
declare @billid varchar(50);
set @billid = 'CGDD001981';
select bill.FID, bill.FBILLNO, entry.FSEQ ,lk.FSTABLENAME as '源单实体标识',
lk.FSID as '源单分录内码', lk.FSBILLID as '源单单据内码',
srcBill.FBILLNO as '采购申请单源单编号'
from T_PUR_POORDER bill
left join T_PUR_POORDERENTRY entry on bill.FID = entry.FID
left join T_PUR_POORDERENTRY_LK lk on entry.FENTRYID = lk.FENTRYID
left join T_PUR_REQUISITION srcBill on lk.FSTABLENAME = 'T_PUR_ReqEntry' and srcBill.FID = lk.FSBILLID
where bill.FBILLNO = @billid
```
link实体本质就是一个子实体，如果关联的是单据头，就用单据头的单据内码和link实体的外键关联；如果关联的是单据体，就用分录内码和link实体关联。
link实体中
FSTABLENAME 记录了上游的关联实体，本案例中就是采购申请单的明细T_PUR_ReqEntry;
FSID 记录了上游关联实体的主键，如果是关联的明细就是源单分录内码，关联的是单据头就是源单单据内码
FSBILLID 记录了上游关联单据的主键
【问题3】插件中使用单据数据包怎么查看对应的源单
```csharp
using Kingdee.BOS.Core.Bill.PlugIn;
using Kingdee.BOS.Core.DynamicForm.PlugIn.Args;
using Kingdee.BOS.Core.Metadata;
using Kingdee.BOS.Core.Metadata.EntityElement;
using Kingdee.BOS.Orm.DataEntity;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace DynamicFormPlugIn.Test
{
[Kingdee.BOS.Util.HotUpdate]
[System.ComponentModel.Description("link实体讲解，获取源单案例")]
public class AdjustTrackResultBillPlugIn : AbstractBillPlugIn
{
public override void BarItemClick(BarItemClickEventArgs e)
{
if (string.Equals("tb_ShowLinkInfo", e.BarItemKey, StringComparison.OrdinalIgnoreCase))
{
this.View.ShowMessage(LinkHelper.GetSrcLinkInfoByBillObj(this.View.BillBusinessInfo, this.Model.DataObject));
}
}
}
public static class LinkHelper
{
/// <summary>
/// 获取link实体
/// </summary>
/// <param name="businessInfo"></param>
/// <returns></returns>
public static LinkEntity GetLinkEntity(BusinessInfo businessInfo)
{
var billForm = businessInfo.GetForm();
if (billForm.LinkSet == null || billForm.LinkSet.LinkEntitys.Count == 0)
return null;
return billForm.LinkSet.LinkEntitys[0];
}
/// <summary>
/// 获取link实体的关联实体
/// </summary>
/// <param name="businessInfo"></param>
/// <returns></returns>
public static Entity GetLinkParentEntiy(BusinessInfo businessInfo)
{
var linkEntity = GetLinkEntity(businessInfo);
if (linkEntity == null)
return null;
var linkParentEntity = businessInfo.GetEntity(linkEntity.ParentEntityKey);
return linkParentEntity;
}
/// <summary>
/// 输出数据包的关联源单关系
/// </summary>
/// <param name="businessInfo">元数据</param>
/// <param name="billDataObj">数据包</param>
/// <returns></returns>
public static string GetSrcLinkInfoByBillObj(BusinessInfo businessInfo, DynamicObject billDataObj)
{
var linkParentEntity = GetLinkParentEntiy(businessInfo);
var linkEntity = GetLinkEntity(businessInfo);
StringBuilder msgBuilder = new StringBuilder();
if (linkParentEntity is HeadEntity)
{
//关联实体在单据头
if (!billDataObj.DynamicObjectType.Properties.ContainsKey(linkEntity.Key))
return string.Empty;
msgBuilder.AppendLine("关联实体在单据头");
DynamicObjectCollection linkObjColl = billDataObj[linkEntity.Key] as DynamicObjectCollection;
ScanLinkDataObj(linkObjColl, (x) => { GetLinkMessage(x, msgBuilder); });
}
