pohdramnd

### 1) Overview
 The `pohdramnd` table serves as the historical header repository for **Sales Purchase Order Amendments**. It stores snapshots of customer purchase orders whenever a revision (amendment) occurs. Each record tracks specific changes to dispatch addresses, payment terms, and validity periods, uniquely identified by the combination of the Purchase Order Number (`PONO`) and the Amendment Number (`amndno`).
 
 ### 2) Column Dictionary
 
 | Column | Type | Nullable | Meaning | Allowed Values | SQL Usage |
 | :--- | :--- | :--- | :--- | :--- | :--- |
 | **index** | integer | NO | Primary key/Identity | | PK for the row |
 | **compcode** | string | YES | Company Identifier | e.g., "DAS" | Filter, Join key |
 | **PONO** | string | YES | Customer Purchase Order Number | e.g., "1112000562" | Join key to details |
 | **custcode** | string | YES | Unique identifier for the Customer | e.g., "LLIPL" | Join to `cust` table |
 | **POdate** | datetime | YES | Original date of the Purchase Order | | Reporting |
 | **desp_address1** | string | YES | Dispatch Address Line 1 | | Address display |
 | **desp_address2** | string | YES | Dispatch Address Line 2 | | Address display |
 | **desp_address3** | string | YES | Dispatch Address Line 3 | | Address display |
 | **mode_payment** | string | YES | Payment Terms/Method | | Financial reporting |
 | **credit_days** | integer | YES | Days allowed for payment | | Credit control |
 | **Desp_thru** | string | YES | Delivery/Dispatch Mode | | Logistics |
 | **Destination** | string | YES | Goods Destination City | | Shipping logic |
 | **chapter** | string | YES | HSN or Excise Chapter reference | | Join to `chapter` table |
 | **locked** | string | YES | Status flag for the record | 'Y', 'N' | Process locking |
 | **amndno** | integer | YES | Amendment sequence number | 0, 1, 2... | Join/Version control |
 | **amnddate** | datetime | YES | Date the amendment was recorded | | Audit trail |
 | **validupto** | datetime | YES | PO Expiry Date | | Expiry checking |
 | **wefdate** | datetime | YES | "With Effect From" Date | | Pricing/Terms validity |
 | **oano** | number | YES | Order Acceptance Number | | Join to `oahdr` |
 | **oadate** | datetime | YES | Order Acceptance Date | | Transaction audit |
 | **remarks** | string | YES | General comments or change notes | | Documentation |
 | **Consignee** | string | YES | Receiving party name | | Shipping logic |
 
 ### 3) Relationships & Join Map
 
 #### Parent Tables
 * **cust**: Join via `compcode` and `custcode` to retrieve customer master details (name, GST, city).
 * **chapter**: Join via `compcode` and `chapter` to identify tax or excise categories.
 * **oahdr**: Join via `compcode` and `oano` to link the amendment back to the internal Order Acceptance.
 
 #### Child/Related Tables
 * **podtlamnd**: Join via `compcode`, `PONO`, `custcode`, and `amndno`. This is the primary child table containing the specific items (line items) associated with this header amendment.
 * **pohdr**: Join via `compcode` and `PONO` to compare amendment data against the current/latest PO header.
 
 #### Join Logic (Authoritative)
 ```sql
 -- Retrieving Amended Header and amended line items
 SELECT *
 FROM dbo.pohdramnd h
 INNER JOIN dbo.podtlamnd d 
  ON h.compcode = d.compcode 
  AND h.PONO = d.pono 
  AND h.amndno = d.amndno 
  AND h.custcode = d.custcode;
 
 -- Retrieving Customer Information for an amendment
 SELECT h.PONO, c.custname
 FROM dbo.pohdramnd h
 INNER JOIN dbo.cust c 
  ON h.compcode = c.compcode 
  AND h.custcode = c.custcode;
 ```