# Child tables and depth links

> Open the nested data some records carry, and pull values in automatically by depth.

A location's tables are listed in the **table menu** - parent tables with their
child tables nested underneath - and you switch between them as you log. On top of
that, some records carry a further table of nested data, and Log can pull related
values in automatically by **depth**.

## Child data on a record

Some records have their own nested table beneath them - specialised data that
belongs to one specific record, such as **soakaway** or **water strike** data
under a particular location. You open it from the record itself:

<Steps>
  <Step title="Select the record">
    In the grid, tap the record whose nested data you want to log.
  </Step>
  <Step title="Open child data">
    Choose **Child data**. Log opens the nested records for that record, with its
    details shown for context above the grid.
  </Step>
  <Step title="Log them">
    Add and edit the nested records as usual. They belong to the record you came
    from.
  </Step>
</Steps>

## Depth links

A **depth link** saves you re-entering data that is already recorded elsewhere at
the same depth. When a field is depth-linked, Log looks up the related table,
finds the record whose depth range contains the depth you are entering, and pulls
its value in for you.

For example, entering a sample at 5.5 m can show the **stratum description** for
that depth automatically, because the description's depth range (its top and base)
contains 5.5 m. You get the geological context inline without opening the
description table.

<Callout type="note" title="Records order by depth">
  Where a table has a depth field, its records are ordered by depth - so strata
  and samples read top to bottom the way you would expect.
</Callout>