mchdr

### 1. Overview
 The `mchdr` table serves as the **Machine Issue Header** (specifically for the **1st Operation** in production). It records the issuance of raw materials from inventory to specific machines on the shop floor to begin the manufacturing process. It links raw material batches (`rmcode`, `mrpno`) to finished or semi-finished items (`itemcode`) and tracks the physical weight issued against the expected piece count.
 
 ### 2. Column Dictionary
 | Column | Type | Nullable | Meaning | Allowed Values | SQL Usage |
 | :--- | :--- | :--- | :--- | :--- | :--- |
 | **index** | integer | No | Primary Key (Internal) | | Primary Key |
 | **compcode** | string | No | Company Identifier | e.g., "DAS", "RF2" | Join Key |
 | **issueno** | integer | No | Unique Issue/Job Card Number | e.g., 287, 1044 | Join Key (to `product2`, `mcdtl`) |
 | **issuedate** | datetime | Yes | Date material was issued to machine | | Filtering/Reporting |
 | **mccode** | string | Yes | Machine Code | e.g., "TRB5", "CNC71(I)" | Join to `machine.mccode` |
 | **noofcoil** | integer | Yes | Number of material coils issued | | Quantitative |
 | **remarks** | string | Yes | General notes or descriptions | | Information |
 | **rmcode** | string | Yes | Raw Material Code | e.g., "ROD12", "BB18.00" | Join to `rmmas.rmcode` |
 | **rmweight** | number | Yes | Total weight of RM issued (Kgs) | | Mass Balance |
 | **mrpno** | integer | Yes | Material Requirement Planning / Batch No | e.g., 3, 58 | Join to `rmincoming.mrpno` |
 | **lotno** | string | Yes | Production Lot Number | e.g., "30408TRB5" | Join to `product2.lotno` |
 | **itemcode** | string | Yes | Target Item being produced | e.g., "CP-128" | Join to `itemmas.itemcode` |
 | **pcs** | integer | Yes | Expected quantity in pieces | | Quantitative |
 | **method_code** | string | Yes | Manufacturing Method Identifier | e.g., "TURN0001" | Join to `manuf_method` |
 | **username** | string | Yes | Application User who created record | | Audit |
 | **useradd** | string | Yes | Audit: User who added record | | Audit |
 | **addtime** | string | Yes | Timestamp of record creation | | Audit |
 | **usermod** | string | Yes | User who last modified record | | Audit |
 | **modtime** | string | Yes | Timestamp of last modification | | Audit |
 | **printflag** | string | Yes | Status of document printing | | Workflow |
 | **heatno** | string | Yes | Metallurgical Heat Number | | Traceability |
 | **cw** | number | Yes | Unit weight (Cheesewt) / Conversion factor | | Weight Calculation |
 | **location** | string | Yes | Physical storage or shop floor location | | Inventory |
 | **mannual_MRN** | string | Yes | Manual Material Receipt Note reference | | Traceability |
 | **wono** | string | Yes | Work Order Number | | Join to `woprodhdr` |
 
 ### 3. Relationships & Join Map
 
 #### Master Data Joins
 * **dbo.itemmas**: Join on `compcode` and `itemcode`. Used to fetch the descriptive name and category of the item being produced.
 * **dbo.machine**: Join on `compcode` and `mccode`. Used to identify machine specifications and shop-floor location.
 * **dbo.rmmas**: Join on `compcode` and `rmcode`. Used to fetch raw material specifications (grade, size, type).
 * **dbo.manuf_method**: Join on `compcode` and `method_code`. Used to identify the routing or process type (e.g., Turning, Forging).
 
 #### Transactional Joins (Downstream Production)
 * **dbo.product2**: Join on `compcode` and `issueno`. This is the primary relationship linking the issue header to actual **First Operation production results** (Accepted vs. Rejected qty).
 * **dbo.mcdtl**: Join on `compcode` and `issueno`. Links to the detail lines of the machine issue.
 * **dbo.rmreturn**: Join on `compcode` and `issueno`. Tracks raw material returned to the store from this specific issue number.
 * **dbo.rmreturnendpcsinhouse**: Join on `compcode` and `issueno`. Tracks end-pieces or scrap returned to stock.
 
 #### Traceability Joins (Upstream)
 * **dbo.rmincoming**: Join on `compcode` and `mrpno`. Links back to the original purchase receipt of the raw material.
 * **dbo.woprodhdr**: Join on `compcode` and `wono` (mapping to `woprodhdr.issueno`). Links the issue to the master Work Order.