> ## Documentation Index
> Fetch the complete documentation index at: https://docs.usebracket.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Configuring your Google Sheet primary key

> Follow these steps to properly set up your Google Sheet primary key

## Summary

To sync Google Sheets using Bracket, each sheet must have a primary field column that contains
unique values. This can be as simple as an integer, or more complex like a UUIDv4.

<Warning>Empty values count as primary key values, which can lead to data mixing in two-way syncs! Be careful to ensure that the primary key field is never empty for any syncs that read from Google Sheets</Warning>

## How to set up your primary key

For **one-way syncs that read from Google Sheets**, the primary key for any populated rows must have a static unique value. This value must never be changed, or data duplication can occur.

For **all other sync configurations**, the primary key must sync with a field in the opposing data source that is itself unique.

<Info>For example, if you are syncing Postgres with G Sheets in a two-way sync, the G Sheet primary key should sync with the Postgres primary key field in the field mapping</Info>

In summary:

| Configuration              | Primary key requirements                                                                                                                                                       |
| -------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| One-way sync from G Sheets | Primary key must be a unique, unchanging value, and identified as the primary key during setup                                                                                 |
| All other configurations   | Primary key must be in the Bracket field mapping, must sync with a field of unique values in the op posing data source, and must be identified as the primary key during setup |