invlotdetail

### 1. Overview
 The `invlotdetail` table serves as a granular traceability layer within the sales and dispatch module. While `invhdr` and `invdtl` track the overall invoice and line-item quantities, `invlotdetail` breaks those dispatches down into specific manufacturing **Lots** and **Heat Numbers**. This table is critical for quality control, FIFO validation, and regulatory compliance, allowing the system to trace exactly which batch of raw material or production run was sent to a customer under a specific invoice number.
 
 ### 2. Column Dictionary
 
 | Column | Type | Nullable | Meaning | Allowed Values | SQL Usage |
 | :--- | :--- | :--- | :--- | :--- | :--- |
 | **index** | integer | No | Primary key for the record. | | PK |
 | **compcode** | string | No | Unique identifier for the company/branch. | e.g., "DAS" | Join Key, Filter |
 | **invno** | integer | No | The invoice number associated with the dispatch. | | Join Key (with `invhdr`) |
 | **invyear** | integer | No | The financial year of the invoice. | e.g., 2021, 2022 | Join Key (with `invhdr`) |
 | **itemcode** | string | No | Internal system code for the finished product. | | Join Key, Grouping |
 | **selfpartno** | string | Yes | The company's internal part number. | | Display/Search |
 | **lotno** | string | No | The specific manufacturing batch or lot identifier. | | Join Key (Traceability) |
 | **advdespqty** | number | No | Quantity dispatched from this specific lot. | > 0 | Summation (Stock out) |
 | **desptype** | string | Yes | Classification of the dispatch. | e.g., "I" (Invoiced) | Filter |
 | **HeatNo** | string | Yes | Metallurgical heat number for material tracking. | | Quality Reporting |
 
 ### 3. Relationships & Join Map
 
 The table acts as a bridge between financial sales records and physical inventory batches.
 
 #### Primary Join Logic
 * **Sales Tracking:** Joins to `invhdr` and `invdtl` using `compcode`, `invno`, and `invyear`. This links specific lots to the customer's invoice.
 * **Inventory Traceability:** Joins to `goodreceipt` or `RMproduct1` using `compcode`, `itemcode`, and `lotno` to trace the origin of the material.
 * **Item Metadata:** Joins to `itemmas` or `saleitemmas` using `itemcode` and `compcode` for descriptive details.
 
 #### Physical Join Map (Based on SCHEMA_MAP)
 * **dbo.invhdr** (Header)
  * `invlotdetail.compcode` = `invhdr.compcode`
  * `invlotdetail.invno` = `invhdr.invno`
  * `invlotdetail.invyear` = `invhdr.invyear`
 * **dbo.invdtl** (Line Items)
  * `invlotdetail.compcode` = `invdtl.compcode`
  * `invlotdetail.invno` = `invdtl.invno`
  * `invlotdetail.invyear` = `invdtl.invyear`
  * `invlotdetail.itemcode` = `invdtl.itemcode`
 * **dbo.goodreceipt** (Stock In Origin)
  * `invlotdetail.compcode` = `goodreceipt.compcode`
  * `invlotdetail.itemcode` = `goodreceipt.itemcode`
  * `invlotdetail.lotno` = `goodreceipt.lotno`
 * **dbo.saleitemmas** (Sales Catalog)
  * `invlotdetail.compcode` = `saleitemmas.compcode`
  * `invlotdetail.itemcode` = `saleitemmas.itemcode` (Note: Often linked via `rmitemcode` in complex queries).