# Universal record identifier A universal record identifier, or URI, uniquely points to a data record. It is similar in structure to a website URL, and usually has the following format: `http://acmehealthcare.com/patient/nRJA4oMMLVA1UltryPiB` In this example, the issuing entity, `Acme Healthcare` is declared first, followed by the type of record—here, this record is for a `patient`. Finally, there is an identifier for the record, `nRJA4oMMLVA1UltryPiB`, which is unique to the Acme Healthcare system. Since the patient identifier is unique within the Acme Healthcare system, and only one `acmehealthcare.com` exists worldwide, the complete URI is globally unique—hence universal. Traditionally, URIs have been generated by centrally managed, always-online systems. In such systems, the server can easily ensure that two different URIs do not “collide”, i.e. they are unique. For example, servers can use timestamps as an input to an algorithm, and the serial nature of time ensures that the resultant URI is unique. However, offline-capable mobile apps are increasingly being used in public health initiatives. When a new record is created using such apps, URIs need to be assigned locally, on a distributed basis. In such systems, suitable algorithms have to be deployed to reduce the risk of URI collision, while being computationally efficient. Contemporary algorithms such as xxhash reduce this risk to one in ten million or lower. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://blog.thelattice.in/readme/universal-record-identifier.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.