# Datasets

Project datasets accumulate knowledge across runs: scan observations are
reconciled into tables you can query, filter, and reuse. Every project can have
up to 100 datasets, and workflows push into them with `step.update_dataset`.

Use this section as a reference for the whole feature:

<table>
<thead>
  <tr>
    <th>
      Page
    </th>
    
    <th>
      What it covers
    </th>
  </tr>
</thead>

<tbody>
  <tr>
    <td>
      <a href="/datasets/overview">
        Overview
      </a>
    </td>
    
    <td>
      Current state vs history, identity, the reserved columns, query surfaces, and limits.
    </td>
  </tr>
  
  <tr>
    <td>
      <a href="/datasets/schema">
        Schemas and identity
      </a>
    </td>
    
    <td>
      Column kinds, naming rules, identity columns, reconciliation, and schema changes.
    </td>
  </tr>
  
  <tr>
    <td>
      <a href="/datasets/workflows">
        Pushing and reading dataset rows
      </a>
    </td>
    
    <td>
      <code>
        step.update_dataset
      </code>
      
       (mapping, upsert/sync modes) and <code>
        step.download_dataset
      </code>
      
      , with a complete asset-tracking workflow.
    </td>
  </tr>
  
  <tr>
    <td>
      <a href="/datasets/sql">
        SQL reference
      </a>
    </td>
    
    <td>
      DuckDB dialect, query scope, pagination and ordering, allowed statements, result types, and examples.
    </td>
  </tr>
  
  <tr>
    <td>
      <a href="/datasets/filters">
        Structured filters
      </a>
    </td>
    
    <td>
      The filter AST and operators, time ranges, where filters run, and the UI filter builder.
    </td>
  </tr>
  
  <tr>
    <td>
      <a href="/datasets/views">
        Saved views
      </a>
    </td>
    
    <td>
      Reusable read-only queries, nesting, cycles, validity, and execution.
    </td>
  </tr>
  
  <tr>
    <td>
      <a href="/datasets/api-cli">
        API and CLI
      </a>
    </td>
    
    <td>
      <code>
        DatasetService
      </code>
      
      , <code>
        DatasetViewService
      </code>
      
      , <code>
        bh dataset
      </code>
      
      , exports, and scopes.
    </td>
  </tr>
</tbody>
</table>