csrnduty

### 1. Overview
 The `csrnduty` table serves as a granular tax and duty breakdown ledger specifically for **Consumable Stores (CS)** within the ERP system. It records individual tax components (such as CGST, SGST, IGST, or CST) associated with a specific Material Receipt Note (`mrpno`). This table is a child entity to receipt headers like `incomconitem`, allowing for multi-line tax calculations per voucher.
 
 ### 2. Column Dictionary
 
 | Column | Type | Nullable | Meaning | Allowed Values | SQL Usage |
 | :--- | :--- | :--- | :--- | :--- | :--- |
 | **index** | integer | NO | Primary Key | 0, 1, 2... | Internal row identifier. |
 | **compcode** | string | NO | Company Identifier | "DAS", etc. | Used in almost all joins for multi-tenant isolation. |
 | **mrpno** | integer | NO | Material Receipt No | 3, 8, 30, 41... | Foreign key to `incomconitem` or `cmrrhdr`. |
 | **duty_code** | integer | NO | Tax/Duty Type Code | 1, 2, 3, 8, 10, 17, 21, 51, 52, 53 | Links to `cdutymas`. (51=CGST, 52=SGST, 53=IGST Likely). |
 | **amount** | number | YES | Financial value of the duty | 112.0, 5.6, etc. | Aggregated for total bill calculations. |
 | **sno** | number | YES | Serial Number | 1.0, 2.0, 3.0... | Order of duties applied within one `mrpno`. |
 | **voudesc** | string | YES | Voucher Description | NULL in sample | Descriptive text for the entry. |
 
 ### 3. Relationships & Join Map
 
 The table is central to the "Input Tax" side of the financial module, specifically for consumables.
 
 #### Primary Header Relationship
 * **incomconitem (compcode, mrpno):** This is the authoritative parent table. `csrnduty` provides the tax breakdown for the consumable items received in `incomconitem`.
  * *SQL*: `FROM incomconitem p JOIN csrnduty r ON p.mrpno = r.mrpno AND p.compcode = r.compcode`
 
 #### Master Data Lookups
 * **cdutymas (compcode, duty_code):** Used to retrieve the name and nature (Tax, Freight, etc.) of the duty code.
  * *SQL*: `FROM csrnduty d JOIN cdutymas m ON d.duty_code = m.duty_code AND d.compcode = m.compcode`
 * **appdutymas (compcode, duty_code):** Likely used to validate applicable duties for specific transaction types.
  * *SQL*: `FROM csrnduty d JOIN appdutymas a ON d.duty_code = a.duty_code AND d.compcode = a.compcode`
 
 #### Parallel Tax Tables
 * **srnduty (compcode, mrpno):** While `csrnduty` is for Consumable Stores (CS), `srnduty` is used for Raw Materials (RM). They are often combined in UNION views like `VATC4` or `viewlp7` to generate a comprehensive purchase register.