erDiagram
    LEVEL_ONES ||--|{ LEVEL_TWOS : "parent of"
    LEVEL_ONES ||--|{ LEVEL_THREES : "parent of"
    LEVEL_ONES ||--|{ ACCOUNTS : "parent of"
    LEVEL_TWOS ||--|{ LEVEL_THREES : "parent of"
    LEVEL_TWOS ||--|{ ACCOUNTS : "parent of"
    LEVEL_THREES ||--|{ ACCOUNTS : "parent of"

    REGISTER_BANKS ||--|{ BANK_BRANCHES : "has"
    REGISTER_BANKS ||--|{ BANK_ACCOUNTS : "has"
    BANK_BRANCHES ||--|{ BANK_ACCOUNTS : "has"
    ACCOUNTS ||--o{ BANK_ACCOUNTS : "linked to"
    BANK_ACCOUNTS ||--o{ BANK_CHEQUES : "has"

    FINANCIAL_YEARS ||--|{ FINANCIAL_PERIODS : "has"
    FINANCIAL_YEARS ||--|{ BUDGETS : "has"
    FINANCIAL_YEARS ||--o{ VOUCHERS : "period"
    FINANCIAL_YEARS ||--o{ EXPENSES : "period"
    FINANCIAL_YEARS ||--o{ FUNDS_TRANSFERS : "period"
    FINANCIAL_YEARS ||--o{ OTHER_INCOMES : "period"
    FINANCIAL_YEARS ||--o{ DEBIT_CREDIT_NOTES : "period"
    FINANCIAL_YEARS ||--o{ OPENING_BALANCES : "period"

    BUDGETS ||--|{ BUDGET_LINES : "details"
    ACCOUNTS ||--o{ BUDGET_LINES : "budgeted for"
    FINANCIAL_PERIODS ||--o{ BUDGET_LINES : "period"

    VOUCHERS ||--|{ TRANSACTIONS : "details"
    ACCOUNTS ||--o{ TRANSACTIONS : "affected by"
    ACCOUNTS ||--o{ OPENING_BALANCES : "has"
    ACCOUNTS ||--o{ DAILY_CLOSING_BALANCES : "has"

    BRANCHES ||--o{ BUDGETS : "location"
    BRANCHES ||--o{ VOUCHERS : "location"
    BRANCHES ||--o{ EXPENSES : "location"
    BRANCHES ||--o{ FUNDS_TRANSFERS : "from/to"
    BRANCHES ||--o{ OTHER_INCOMES : "location"
    BRANCHES ||--o{ DEBIT_CREDIT_NOTES : "location"
    BRANCHES ||--o{ OPENING_BALANCES : "location"
    BRANCHES ||--o{ DAILY_CLOSING_BALANCES : "location"

    VOUCHERS ||--o{ EXPENSES : "references"
    VOUCHERS ||--o{ FUNDS_TRANSFERS : "references"
    VOUCHERS ||--o{ OTHER_INCOMES : "references"
    VOUCHERS ||--o{ DEBIT_CREDIT_NOTES : "references"

    LEVEL_ONES {
        bigint id PK
        string level_one_name
        string level_one_code
        boolean is_active
    }
    LEVEL_TWOS {
        bigint id PK
        bigint level_one_id FK
        string level_two_name
        string level_two_code
        boolean is_active
    }
    LEVEL_THREES {
        bigint id PK
        bigint level_one_id FK
        bigint level_two_id FK
        string level_three_name
        string level_three_code
        boolean is_active
    }
    ACCOUNTS {
        bigint id PK
        bigint level_one_id FK
        bigint level_two_id FK
        bigint level_three_id FK
        string account_name
        string account_code
        boolean is_active
    }
    REGISTER_BANKS {
        bigint id PK
        string bank_name
        string bank_code
        string bank_swift_code
        text head_office_address
        string contact_person
        boolean is_active
    }
    BANK_BRANCHES {
        bigint id PK
        bigint bank_id FK
        bigint region_id FK
        string branch_name
        string branch_code
        string branch_address
        string branch_contact_number
        string manager_name
        boolean is_active
    }
    BANK_ACCOUNTS {
        bigint id PK
        string account_number
        string account_name
        string account_type
        bigint bank_id FK
        bigint bank_branch_id FK
        bigint account_id FK
        boolean is_active
    }
    BANK_CHEQUES {
        bigint id PK
        bigint bank_account_id FK
        string cheque_number
        date issue_date
        date pay_date
        decimal amount
        string payee_name
        enum status
        string reference_type
        integer reference_id
        text remarks
    }
    FINANCIAL_YEARS {
        bigint id PK
        string year_code
        string financial_year
        date start_date
        date end_date
        enum status
    }
    FINANCIAL_PERIODS {
        bigint id PK
        bigint financial_year_id FK
        string period_code
        enum period_type
        date start_date
        date end_date
        enum status
    }
    BUDGETS {
        bigint id PK
        string budget_name
        bigint financial_year_id FK
        bigint branch_id FK
        enum status
        text remarks
    }
    BUDGET_LINES {
        bigint id PK
        bigint budget_id FK
        bigint account_id FK
        bigint financial_period_id FK
        decimal budgeted_amount
        decimal actual_amount
        decimal remaining_amount
        boolean overspend_allowed
    }
    VOUCHERS {
        bigint id PK
        bigint branch_id FK
        bigint created_by FK
        bigint financial_year_id FK
        json financial_period_ids
        enum voucher_type
        string voucher_number
        date voucher_date
        text narration
        enum reference_type
        bigint reference_id
        boolean posted
        enum status
        json debit
        json credit
        json cheque
    }
    TRANSACTIONS {
        bigint id PK
        bigint voucher_id FK
        bigint account_id FK
        decimal debit
        decimal credit
        text description
        string reference_type
        integer reference_id
    }
    EXPENSES {
        bigint id PK
        string expense_number
        date expense_date
        decimal amount
        enum mode_of_payment
        enum status
        string remarks
        bigint created_by FK
        bigint branch_id FK
        bigint financial_year_id FK
        json financial_period_ids
        json debit
        json credit
        json cheque
    }
    FUNDS_TRANSFERS {
        bigint id PK
        string transfer_number
        date transfer_date
        date received_date
        decimal amount
        enum mode_of_payment
        enum status
        json debit
        json credit
        json cheque
        string remarks
        bigint from_branch_id FK
        bigint to_branch_id FK
        bigint created_by FK
        bigint branch_id FK
        bigint financial_year_id FK
        json financial_period_ids
    }
    OTHER_INCOMES {
        bigint id PK
        string income_number
        date income_date
        decimal amount
        enum mode_of_payment
        enum status
        json debit
        json credit
        json cheque
        string remarks
        bigint created_by FK
        bigint branch_id FK
        bigint financial_year_id FK
        json financial_period_ids
    }
    DEBIT_CREDIT_NOTES {
        bigint id PK
        string note_number
        date note_date
        decimal amount
        enum note_classification
        enum recipient_type
        bigint recipient_id
        enum type
        text remarks
        bigint created_by FK
        bigint branch_id FK
        bigint financial_year_id FK
        json financial_period_ids
    }
    OPENING_BALANCES {
        bigint id PK
        bigint account_id FK
        bigint financial_year_id FK
        bigint branch_id FK
        decimal opening_debit
        decimal opening_credit
        text narration
        boolean is_migrated
    }
    DAILY_CLOSING_BALANCES {
        bigint id PK
        bigint account_id FK
        bigint branch_id FK
        date closing_date
        decimal opening_balance
        decimal total_debit
        decimal total_credit
        decimal closing_balance
    }