--- title: "categorical-constant" slug: "categorical-constant-parser" updated: 2022-07-27T22:51:03Z published: 2022-07-27T22:51:03Z canonical: "code.tag.bio/categorical-constant-parser" --- > ## Documentation Index > Fetch the complete documentation index at: https://code.tag.bio/llms.txt > Use this file to discover all available pages before exploring further. # categorical-constant The `categorical-constant` **parser** does not load any data from a source data table. On the other hand, it will assign every **entity** identified by its associated **table** object into a single categorical **variable** within a **collection**. ``` { "parser_type": "categorical-constant", "table_alias": "tata", "column": "ccc1", "value": "Yes", "collection": "collection_name", "variable": "variable_name" } ``` At first, it may seem useless to assign every **entity** into the same categorical **variable**. But it's not *every* **entity** - because this **parser** operates in conjunction with a **table** object, it's possible that the source data table contains rows that only match with a subset of **entities** loaded from the *entity_table*. Thus, this **parser** is able to flag all entities that were present in an *other_table*. ## value **usage: *required*** The value attribute becomes the variable name.