docs(notes): add transaction table documentation

Author: lzwjava

notes/2025-03-25-transaction-table-en.md

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+---
+title: Transaction Table
+lang: en
+layout: post
+audio: false
+translated: false
+generated: true
+---
+
+A **transaction table** in a banking system typically stores details of all financial transactions processed by the bank. This table is essential for tracking customer transactions, reconciling accounts, and ensuring regulatory compliance.  
+
+---
+
+### **Key Fields in a Banking Transaction Table**  
+
+| **Field Name**           | **Data Type** | **Description** |
+|--------------------------|--------------|----------------|
+| **Transaction_ID**       | `VARCHAR` / `BIGINT` | Unique identifier for each transaction |
+| **Account_Number**       | `VARCHAR` / `BIGINT` | Customer’s bank account number involved in the transaction |
+| **Transaction_Type**     | `VARCHAR` | Type of transaction (e.g., DEPOSIT, WITHDRAWAL, TRANSFER, PAYMENT) |
+| **Transaction_Amount**   | `DECIMAL(15,2)` | Amount involved in the transaction |
+| **Currency_Code**        | `VARCHAR(3)` | Currency of the transaction (e.g., USD, EUR, INR) |
+| **Transaction_Date**     | `DATETIME` | Timestamp when the transaction occurred |
+| **Value_Date**           | `DATETIME` | Date when the transaction is settled or processed |
+| **Debit_Credit_Flag**    | `CHAR(1)` | Indicator whether the transaction is a **Debit ('D')** or **Credit ('C')** |
+| **Counterparty_Account** | `VARCHAR` | Destination account number (if applicable) |
+| **Transaction_Mode**     | `VARCHAR` | Payment method (SWIFT, RTGS, NEFT, ACH, UPI, Card, Wallet, etc.) |
+| **Transaction_Status**   | `VARCHAR` | Status of the transaction (PENDING, SUCCESS, FAILED, REVERSED) |
+| **Reference_Number**     | `VARCHAR` | Unique identifier for external systems (e.g., SWIFT Reference, UTR, UPI Transaction ID) |
+| **Transaction_Description** | `TEXT` | Additional details about the transaction (e.g., “Bill Payment - Electricity”, “Salary Credit”) |
+| **Branch_Code**          | `VARCHAR(10)` | Identifier for the bank branch processing the transaction |
+| **Transaction_Fee**      | `DECIMAL(10,2)` | Any charges deducted for the transaction |
+| **Exchange_Rate**        | `DECIMAL(10,6)` | Exchange rate applied if currency conversion is involved |
+| **Initiating_Channel**   | `VARCHAR` | Channel used for transaction (ATM, Mobile Banking, Internet Banking, POS, Teller) |
+| **Fraud_Check_Status**   | `VARCHAR` | Status of fraud detection (e.g., PASSED, FLAGGED, UNDER REVIEW) |
+| **Reversal_Transaction_ID** | `VARCHAR` | If reversed, links to the original transaction ID |
+
+---
+
+### **Example Transaction Records**  
+
+| Transaction_ID | Account_Number | Type      | Amount  | Currency | Date                 | Debit/Credit | Counterparty | Mode   | Status  |
+|---------------|---------------|-----------|---------|----------|----------------------|--------------|--------------|--------|---------|
+| 100001       | 123456789012   | DEPOSIT   | 1000.00 | USD      | 2025-03-25 10:15:00 | C            | -            | ATM    | SUCCESS |
+| 100002       | 123456789012   | TRANSFER  | 500.00  | USD      | 2025-03-25 12:30:00 | D            | 987654321098 | SWIFT  | SUCCESS |
+| 100003       | 987654321098   | TRANSFER  | 500.00  | USD      | 2025-03-25 12:30:00 | C            | 123456789012 | SWIFT  | SUCCESS |
+| 100004       | 123456789012   | PAYMENT   | 50.00   | USD      | 2025-03-25 14:00:00 | D            | Utility Co.  | ACH    | PENDING |
+
+---
+
+### **How These Fields Are Used in Banking**  
+1. **Transaction Tracking:** Every transaction has a unique ID and can be tracked through its status.  
+2. **Account Reconciliation:** Helps in matching debits and credits for accurate financial records.  
+3. **Fraud Detection:** Suspicious transactions can be flagged using fraud check status and monitoring transaction patterns.  
+4. **Regulatory Reporting:** Ensures compliance with financial regulations (AML, KYC, Basel III).  
+5. **Customer Service:** Helps banks resolve disputes and inquiries regarding failed or pending transactions.  
+
+Would you like a more detailed schema with SQL queries? 🚀