> For the complete documentation index, see [llms.txt](https://docs.fact-finder.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.fact-finder.com/integration/integrating-the-navigation-module/restricting-to-a-main-category.md).

# Restricting to a main category

Because the Navigation module works with the same data as Search, navigating the product range means applying a filter or filter combination across the full product set. The field type matters here. FactFinder supports two main types:

#### Simple data field

Each simple data field stores one hierarchy level. A FactFinder setup that uses this structure has several related fields to represent the full hierarchy. These fields usually share the same base name and differ only by numbering, such as `Category0`, `Category1`, and `Category2`.

Example data:

|            |                  |
| ---------- | ---------------- |
| Field name | Database content |
| category0  | Clothing         |
| category1  | Trousers         |
| category2  | Jeans            |

#### Category path field

In this case, the full navigation hierarchy is stored in a dedicated FactFinder category path field. Note that the database content does not necessarily match the content of the export file.

|            |                             |
| ---------- | --------------------------- |
| Field name | Database content            |
| category   | \|Clothing/Trousers/Jeans\| |

### Filtering for a simple data field

The default name for this kind of field in FactFinder is `category0`. If you want to navigate to the category `Clothing`, the navigation call must pass the filter parameter `filter=category0:Clothing`. A corresponding REST call looks like this:

```language-plaintext
../rest/{apiversion}/navigation/{channel}?filter=category0:Clothing
```

### Filtering for a category path field

If you want to navigate a field that contains a category path, the navigation call must pass the filter parameter `filter=category:Clothing`.

For the example above, the corresponding REST call looks like this:

```language-plaintext
../rest/{apiversion}/navigation/{channel}?filter=category:Clothing
```


---

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