> For the complete documentation index, see [llms.txt](https://chembl.gitbook.io/unichem/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://chembl.gitbook.io/unichem/definitions/what-is-an-assignment.md). # What is an Assignment? ## Assignments An 'Assignment' refers to the mapping of a src\_compound\_id to a particular structure in UniChem. Thus the src\_compound\_d 'CHEMBL2' is assigned to the InChI 'InChI=1S/C16H13ClN2O/c1-19-14-8-7-12(17)9-13(14)16(18-10-15(19)20)11-5-3-2-4-6-11/h2-9H,10H2,1H3' in UniChem. In the database, all assignments are classified as either 'current' ('1') or 'obsolete' ('0'). A 'current' assignment means that this assignment exists in the most recently loaded data release from the source. An 'obsolete' assignment means that the most recent data release does not have this assignment, but an earlier release from the same source did make this assignment. When querying UniChem via the [Home / Search page](https://www.ebi.ac.uk/unichem/) the classifications of assignments are shown in the field 'Assigned in Latest Release'. If an assignment is current ('Yes', or '1' in the database) then the adjacent field in the results table ('Last release when current') will display nothing. However, if the assignment is obsolete then this adjacent field will indicate the last data release when this assignment was current. This field may contain a date or a release version number, depending on the system used by the original source. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## 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, and the optional `goal` query parameter: ``` GET https://chembl.gitbook.io/unichem/definitions/what-is-an-assignment.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. 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.