If you're from a more traditional database background, you can think of them as a resource identifier, an attribute name, and an attribute value.

如果您来自比较传统的数据库背景，可能会把它们看作资源标识符、属性名称和属性值。

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Passengers vetted via background checks would have a biometric identifier, such as their fingerprint or iris pattern, in their passport or other travel document.

BBC: New measures in airport security