# Glossary of Terms

**Term:**  Source Data Release\
 **Description:**  (SDR) A data set obtained from a source, constituting all the current assignments in the source. Sometimes simply referred to as a 'Data Release'. Not to be confused with a UDR.\
\
**Term:**  src\_release\_number\
 **Description:**  A release number, as defined by the source, for a particular SDR. Each source is defined as having either a 'date' or a 'number' for identifying different SDRs.\
\
**Term:**  src\_release\_date\
 **Description:**  A release date, as obtained from the source, for a particular SDR. Each source is defined as having either a 'date' or a 'number' for identifying different SDRs.\
\
**Term:**  Release\_U\
 **Description:**  (RU) UniChem-generated integers (One for each source) incremented by 1 for each Data Load from that source. For example, if, for a given source, the CRU is 4 then a total of 4 SDRs have been loaded for this source.\
\
**Term:**  Current Release\_U\
**Description:**  (CRU) The current Release\_U for a particular source\
\
**Term:**  Data Load\
**Description:**  The process of adding a single 'Source Data Release' into UniChem.\
\
**Term:**  UniChem Load Index\
**Description:**  (UC\_LOAD\_INDEX, or ULI) A UniChem-generated integer incremented by 1 for each successful Data Load from any source. The current ULI therefore indicates the total number of separate Data Loads from all sources.\
\
**Term:**  UniChem Data Release\
**Description:**  (UDR) Data is loaded into UniChem in a 'production' instance of the database. After several data loads, a copy is made of this database and is made available to users. Each new UDR may therefore contain several additional ULI's compared to the last UDR\
\
**Term:**  UniChem Data Release Index\
**Description:**  (UDRI) An integer indicating the number of the UDR. Also called a 'UC\_RELEASE\_NUMBER', or 'UC Rel No.'\
\
**Term:**  Query Data Type\
**Description:**  (QDT) The permitted Data Types for querying UniChem. Four such Types exist: src\_id, src\_compound\_id, InChI and InChI Key. As defined [elsewhere](http://howe.ebi.ac.uk:3000/info/srcidExplain)<br>


---

# 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://chembl.gitbook.io/unichem/definitions/glossary-of-terms.md?ask=<question>
```

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.