在XML中，节点之前的"tg:“意味着什么？

Question

我有一个来自需要匹配的外部系统的XML示例。然而，示例XML具有以下格式；

<tg:order tg:job_id="SC10268" tg:site_code="SC" tg:replace="true">
        <tg:job_description>STJ Import - AUG 2007</tg:job_description>
        <tg:order_qty>176277</tg:order_qty>
        <!-- finishing style should be WS for saddle stitched or PB for perfect bound -->
        <tg:finishing_style>PB</tg:finishing_style>
        <!-- overall finished trim size and extent -->
        <tg:depth>8.25</tg:depth>
        <tg:width>10.875</tg:width>
        <tg:cover_pagination>4</tg:cover_pagination>
        <tg:text_pagination>240</tg:text_pagination>
        <!-- deadline dates for the job are specified here -->
        <tg:delivery_commence_date>2007-11-04</tg:delivery_commence_date>
        <tg:delivery_complete_date>2007-11-05</tg:delivery_complete_date>
        <!-- job site and managing printer should default to your site code we set up for the trial -->
        <tg:job_site>SC</tg:job_site>
        <tg:managing_printer>SC</tg:managing_printer>
        <!-- job site and managing printer should default to true for the trial -->
        <tg:is_managing_printer>true</tg:is_managing_printer>
        <!-- customer purchase order reference if known -->
        <tg:cust_order_ref>776030</tg:cust_order_ref>
        <!-- customer code should be a unique reference that we will use to add customer detail and avoid duplicates -->
        <!-- see seperate company import specification for further company details -->
        <!-- Customer code MUST match an CompanyShortCode in the Company DB -->
        <tg:cust_code>Sears</tg:cust_code>
        <!-- add as many job related contacts as you need -->
        <tg:cust_contact tg:cust_contact_code="jill.summers@sears.com"/>
        <tg:cust_contact tg:cust_contact_code="simon.caldwell@sears.com"/>
        <!-- account exec / CSR details - the email address will be used as a unique key to avoid duplicates -->
        <!-- we will add new CSR's (based on email address to the list of available CSR's -->
        <tg:site_cce_name>Cathy Noble</tg:site_cce_name>
        <tg:site_cce_phone>(847) 466 1008</tg:site_cce_phone>
        <tg:site_cce_mobile>(847) 477 2008</tg:site_cce_mobile>
        <tg:site_cce_email>cathy.noble@superior.com</tg:site_cce_email>
        <!-- sales rep details - the email address will be used as a unique key to avoid duplicates -->
        <!-- we will add new sales reps (based on email address to the list of available sales reps -->
        <tg:sales_person_name>Sam Brown</tg:sales_person_name>
        <tg:sales_person_phone>(847) 466 1001</tg:sales_person_phone>
        <tg:sales_person_mobile>(847) 477 2001</tg:sales_person_mobile>
        <tg:sales_person_email>sam.brown@superior.com</tg:sales_person_email>
</tg:order>

每个节点之前的"tg:“是什么意思？这是XML的一部分，还是来自另一个系统？谢谢大家！

Answer 1

它是相关模式的命名空间的前缀。每个xml文档可能包含名称空间，也可能不包含名称空间。

应该声明名称空间和相关前缀，通常在根元素中，例如：

<root xmlns:tg="http://www.w3.org/TR/html4/theTGprefixnamespace">

在此之后，属于名称空间的任何元素都应该在其名称前加上前缀：

<root xmlns:tg="http://www.w3.org/TR/html4/theTGprefixnamespace">
    <tg:item />
</root>

相关阅读从w3schools。