itemrmchwt

### 1) Overview
 The `itemrmchwt` table is a critical Bill of Materials (BOM) mapping table that defines the relationship between a finished/semi-finished **Item** and its constituent **Raw Material (RM)**. 
 
 The primary purpose of this table is to store the **"Cheese Weight"**—the gross weight of the raw material required to produce a single unit of the item. This value is used extensively in production planning, material requirement generation (MRP), and scrap calculation (Scrap = Cheese Weight - Finished Weight). It also supports manufacturing method variations via the `method_code`.
 
 ### 2) Column dictionary
 
 | Column | Type | Nullable | Meaning | Allowed Values | SQL Usage |
 | :--- | :--- | :--- | :--- | :--- | :--- |
 | **index** | integer | NO | Primary key for the record. | Auto-incrementing | `PRIMARY KEY` |
 | **compcode** | string | NO | Unique identifier for the company/branch. | e.g., "DAS", "OMA" | Joined with almost all tables. |
 | **itemcode** | string | NO | The unique identifier for the produced item. | e.g., "GPDNTVS" | Joins to `itemmas`, `saleitemmas`. |
 | **rmcode** | string | NO | The unique identifier for the raw material used. | e.g., "49.2EN8D" | Joins to `rmmas`, `rmincoming`. |
 | **method_code** | string | YES | The specific manufacturing method or process code. | e.g., "TURN0001" | Joins to `manuf_method`. |
 | **cheesewt** | number | YES | The gross input weight of the RM per unit of Item. | e.g., 1580.0 | Used to calculate `ScrapWeight`. |
 | **active** | string | YES | Status flag indicating if this BOM entry is active. | "Y", "N", " " | Filters valid BOM mappings. |
 | **auth_flag** | string | YES | Authorization flag for quality/managerial approval. | "Y", "N" | Used in production views. |
 | **Length_To_ChWeight** | number | YES | Conversion factor if RM is measured in length (MTR). | e.g., 0.0 | Used as override for `cheesewt`. |
 | **RMUoM** | string | YES | Unit of measure for the raw material. | "KGS", "MTR" | Used for unit conversions. |
 
 ### 3) Relationships & join map
 
 #### Logical Joins (Based on SCHEMA_MAP)
 The table acts as a bridge between Item Masters and Raw Material Masters:
 
 1. **Item Master (`dbo.itemmas`)**: 
  * `itemrmchwt.itemcode` = `itemmas.itemcode`
  * `itemrmchwt.compcode` = `itemmas.compcode`
  * *Usage:* To retrieve item names and finished weights for scrap analysis.
 
 2. **Raw Material Master (`dbo.rmmas`)**:
  * `itemrmchwt.rmcode` = `rmmas.rmcode`
  * `itemrmchwt.compcode` = `rmmas.compcode`
  * *Usage:* To identify the specific grade and properties of the raw material.
 
 3. **Manufacturing Methods (`dbo.manuf_method`)**:
  * `itemrmchwt.method_code` = `manuf_method.method_code`
  * `itemrmchwt.compcode` = `manuf_method.compcode`
  * *Usage:* To differentiate between different production routes for the same item.
 
 4. **Sales Item Mapping (`dbo.saleitemmas`)**:
  * `itemrmchwt.itemcode` = `saleitemmas.rmitemcode` (Likely)
  * *Context:* Used in sales reports to calculate the raw material value/weight consumed for domestic or export sales.
 
 5. **Job Records (`dbo.jobhdr`)**:
  * `itemrmchwt.itemcode` = `jobhdr.itemcode`
  * `itemrmchwt.rmcode` = `jobhdr.rmcode`
  * *Context:* Validating input weight against actual raw material issued for a job.