Description:
Either an invoice or a credit note in the Accounts Payable system.

PRIMARY KEY
a_ap_document_id_i integer default: 0 NOT NULL	Unique key for this record

UNIQUE KEY
a_ledger_number_i integer NOT NULL	Reference to the ledger for this invoice.	a_ledger, a_account
a_ap_number_i integer NOT NULL	A unique key (together with the ledger number) to identify this document.

p_partner_key_n bigint NOT NULL	Reference to the supplier that sent this invoice.	a_ap_supplier
a_credit_note_flag_l boolean default: '0' NOT NULL	A flag to indicate if this document is an invoice or a credit note.
a_document_code_c varchar (30)	The code given on the document itself (be it invoice or credit note). This will have to be unique for each supplier.
a_reference_c varchar (100)	Some kind of other reference needed.
a_date_issued_d date default: CURRENT_DATE NOT NULL	The date when this document was issued.
a_date_entered_d date default: CURRENT_DATE NOT NULL	The date when this document was entered into the system.
a_credit_terms_i integer default: 0	Credit terms allowed for this invoice.
a_total_amount_n numeric (24, 10) default: 0 NOT NULL	The total amount of money that this document is worth.
a_currency_code_c varchar (16) NOT NULL	the currency of the document
a_exchange_rate_to_base_n numeric (24, 10)	The exchange rate to the base currency at the time that the document was issued.
a_discount_percentage_n numeric (24, 10)	The percentage discount you get for early payment of this document in the case that it is an invoice.
a_discount_days_i integer	The number of days that the discount is valid for (0 for none).
a_ap_account_c varchar (16)	Reference to the AP Account to debit/credit when posting/paying the document.	a_account
a_last_detail_number_i integer default: 0 NOT NULL	The number of the last item for this document. This is used simply to quickly get the next number if items are added.
a_document_status_c varchar (16)	The current status of the invoice. The value can (for now) be one of: OPEN, APPROVED, POSTED, PARTPAID, or PAID.
s_date_created_d date default: CURRENT_DATE	The date the record was created.
s_created_by_c varchar (20)	User ID of who created this record.	s_user
s_date_modified_d date	The date the record was modified.
s_modified_by_c varchar (20)	User ID of who last modified this record.	s_user
s_modification_id_t timestamp default: CURRENT_TIMESTAMP	This identifies the current version of the record.
FOREIGN KEY a_ap_document_fk1: a_ledger_number_i => a_ledger a_ap_document_fk2: p_partner_key_n => a_ap_supplier a_ap_document_fk3: a_ledger_number_i;a_ap_account_c => a_account a_ap_document_fkcr: s_created_by_c => s_user a_ap_document_fkmd: s_modified_by_c => s_user
REFERENCED BY a_crdt_note_invoice_link, a_crdt_note_invoice_link, a_ap_document_detail, a_ap_document_payment, a_ep_document_payment