itemcustrate

### 1) Overview
 The `itemcustrate` table serves as a mapping and pricing configuration ledger between Items and Customers. It defines customer-specific sales rates, part numbers, and drawing references, along with detailed packaging instructions (mode of pack, quantity, and surface finish). This table is frequently used in reporting stored procedures (e.g., `jobwork1st2ndoperation_rpt`, `istitemwisedetail_rpt`) to resolve which customer is associated with specific item production or stock.
 
 ### 2) Column Dictionary
 
 | Column | Type | Nullable | Meaning | Allowed Values | SQL Usage |
 | :--- | :--- | :--- | :--- | :--- | :--- |
 | **index** | integer | No | Primary Key / Internal Identity | | Internal record tracking. |
 | **compcode** | string | No | Company Code | "DAS", "BAM", etc. | Primary join key for multi-tenant data isolation. |
 | **itemcode** | string | No | Unique Item Identifier | "CP-003", "FGS" | Join key to `itemmas` and production tables. |
 | **custcode** | string | No | Customer Code | "QHTL(M)", "QH(C)" | Join key to `cust` table. |
 | **partno** | string | Yes | Customer-specific Part Number | | Cross-referencing internal items to customer IDs. |
 | **sale_rate** | number | Yes | Unit Selling Price for this specific Customer/Item | | Financial calculation of sales value. |
 | **itemname** | string | Yes | Item Name / Description | | Descriptive reporting. |
 | **surf_finish** | string | Yes | Surface Finish requirement | | Quality/Production specifications. |
 | **packqty** | integer | Yes | Standard Quantity per Outer Pack | | Logistics and shipping calculations. |
 | **modeofpack** | string | Yes | Primary Packaging Type | "BOX", "BIN", "TANKY" | Packing slip generation. |
 | **custdrawing** | string | Yes | Customer Drawing Number/Reference | | Technical documentation link. |
 | **submodeofpack** | string | Yes | Secondary/Inner Packaging Type | | Detailed packing instructions. |
 | **subpackqty** | number | Yes | Quantity within the sub-pack | | Detailed packing instructions. |
 
 ### 3) Relationships & Join Map
 
 Based on `SCHEMA_MAP` and the logic identified in `REFERENCE_JSON`, the following joins are authoritative:
 
 #### Mandatory Joins (Same-Name Columns)
 * **dbo.itemmas**: Join on `compcode` and `itemcode`. Used to fetch internal item master details.
 * **dbo.cust**: Join on `compcode` and `custcode`. Used to resolve Customer Names and Group details (referenced in `TotalItemStock_without_Vendor`).
 * **dbo.invdtl / dbo.podtl**: Join on `itemcode` (and `compcode`) to apply customer-specific rates during invoicing or order processing.
 
 #### Likely Joins (Inferred from Usage)
 * **dbo.job / dbo.jobhdr**: Join on `itemcode` and `compcode`. Used in production reports to identify which customer an active job card belongs to.
 * **dbo.saleitemmas**: Join on `itemcode` and `compcode`. Links the sales-specific item attributes to the customer rate mapping.