sequenceDiagram
    participant User
    participant Payment Service
    participant DB
    participant External Gateway

    User->>Payment Service: Initiate Payment
    activate Payment Service
    Payment Service->>DB: Begin Transaction
    activate DB
    DB-->>Payment Service: Transaction Started
    deactivate DB
    Payment Service->>External Gateway: Request Payment Authorization
    activate External Gateway

    alt Successful Authorization
        External Gateway-->>Payment Service: Authorization Success
        Payment Service->>DB: Commit Transaction
        activate DB
        DB-->>Payment Service: Transaction Committed
        deactivate DB
        Payment Service-->>User: Payment Successful
    else Authorization Failed
        External Gateway-->>Payment Service: Authorization Failure
        Payment Service->>DB: Rollback Transaction
        activate DB
        DB-->>Payment Service: Transaction Rolled Back
        deactivate DB
        Payment Service-->>User: Payment Failed
    end

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