这是我的 XML 测试代码：
<?xml version="1.0" encoding="UTF-8"?>
<Invoice xmlns:qdt="urn:oasis:names:specification:ubl:schema:xsd:QualifiedDatatypes-2" xmlns:ccts="urn:oasis:names:specification:ubl:schema:xsd:CoreComponentParameters-2" xmlns:stat="urn:oasis:names:specification:ubl:schema:xsd:DocumentStatusCode-1.0" xmlns:cbc="urn:oasis:names:specification:ubl:schema:xsd:CommonBasicComponents-2" xmlns:cac="urn:oasis:names:specification:ubl:schema:xsd:CommonAggregateComponents-2" xmlns:udt="urn:un:unece:uncefact:data:draft:UnqualifiedDataTypesSchemaModule:2" xmlns="urn:oasis:names:specification:ubl:schema:xsd:Invoice-2">
<cbc:ID>A00095678</cbc:ID>
<cbc:IssueDate>2005-06-21</cbc:IssueDate>
<cac:AccountingSupplierParty>
</cac:AccountingSupplierParty>
<cac:AccountingCustomerParty>
</cac:AccountingCustomerParty>
<cac:LegalMonetaryTotal>
<cbc:PayableAmount currencyID="GBP">107.50</cbc:PayableAmount>
</cac:LegalMonetaryTotal>
<cac:InvoiceLine>
<cbc:ID>A</cbc:ID>
<cbc:LineExtensionAmount currencyID="GBP">100.00</cbc:LineExtensionAmount>
<cac:Item>
</cac:Item>
</cac:InvoiceLine>
</Invoice>
我将由于 minOccurs="1" 而需要的唯一元素放入 UBL.xsd 文件中。
当我尝试在此网站
上验证我的 XML 时[BR-01]-An Invoice shall have a Specification identifier (BT-24).
[BR-04]-An Invoice shall have an Invoice type code (BT-3).
[BR-05]-An Invoice shall have an Invoice currency code (BT-5).
[BR-06]-An Invoice shall contain the Seller name (BT-27).
[BR-07]-An Invoice shall contain the Buyer name (BT-44).
[BR-08]-An Invoice shall contain the Seller postal address.
[BR-10]-An Invoice shall contain the Buyer postal address (BG-8).
[BR-CO-18]-An Invoice shall at least have one VAT breakdown group (BG-23).
我明白错误的含义，我的问题更多： UBL.xsd 文件说这些元素是强制性的是什么？我将必须生成有关其他 .xsd 文件的文件，并且我想了解哪些元素是必需的。