# Inputs

This guide introduces you to the concept of inputs in Profiles and shows how to use them in your Profiles project.

## Overview

The foundation of every companies data is the source files and data tables - these are the inputs that go into every data product a company produces. 

In Profiles, `inputs` contain the IDs for identity graphs and the fields that build into a Customer360 (C360). They can be database tables or views, S3 buckets, and/or CSV files.

**SQL Keyword**: `FROM`

## Usage

You can define `inputs` in the [`inputs.yaml`]({{< ref "profiles/dev-docs/inputs-yaml/" >}}) file, as shown:

```yaml
inputs:
  - name: rsIdentifies
    app_defaults:
      table: autotrack_data.autotrack.identifies
      occurred_at_col: timestamp
      ids:
        - select: "user_id"
          type: user_id
          entity: user
        - select: "anonymous_id"
          type: anonymous_id
          entity: user
        - select: "lower(email)"
          type: email
          entity: user
  - name: rsPages
    app_defaults:
      table: autotrack_data.autotrack.pages
      occurred_at_col: timestamp
      ids:
        - select: "user_id"
          type: user_id
          entity: user
        - select: "anonymous_id"
          type: anonymous_id
          entity: user
```

## Best practices

- Though it is possible to bring in data sources that only have one identifier column for your entity, it is best to have two or more columns, especially for `inputs` that you want to use as a source for the `id_stitcher` model.
- If any of your ID columns are not of the string data type, then you must case them explicitly, as shown below:

```yaml
      ids:
        - select: "CAST(user_id AS VARCHAR)"
          type: user_id
          entity: user
```

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