> ## Documentation Index > Fetch the complete documentation index at: https://docs.sourcemedium.com/docs/llms.txt > Use this file to discover all available pages before exploring further. # Data Definitions > Canonical definitions for the fields and business rules that show up across SourceMedium tables, dashboards, and recipes. These pages document the **definitions that matter** across SourceMedium: * The fields that appear across many tables (and therefore many dashboards + recipes) * The business rules behind how we normalize, map, and dedupe data * The “gotchas” that most often cause analysis to drift If you’re here for SQL examples, the fastest starting point is the [SQL Query Library](/data-activation/template-resources/sql-query-library). How to filter orders correctly using `is_order_sm_valid`. Net vs gross vs total revenue (and how refunds/discounts flow through). Refund components, sign conventions, and common refund-rate patterns. Subscription classification fields and “first vs recurring” flags. How `sm_channel` and `sm_sub_channel` are assigned (and how overrides work). How UTM fields are normalized and how to query them safely. How we avoid double-counting when multiple event streams exist.