## Things to Keep in Mind
### During Setup
{% hint style="warning" %}
**All Postgres tables must have a primary key**\
We use the primary key to keep your data in sync. See [Postgres snippets](https://docs.whalesync.com/connectors/postgres/primary-key-snippets) for additional detail.
{% endhint %}
{% hint style="warning" %}
**Primary keys must be auto-generated**\
Make sure your primary keys are generated by your database (i.e. have a default value). See [Postgres snippets](https://docs.whalesync.com/connectors/postgres/primary-key-snippets) for additional detail.
{% endhint %}
{% hint style="warning" %}
**Double-check that the Postgres account you use with Whalesync has access** **to the tables you want to map.**
{% endhint %}
### After Setup
{% hint style="danger" %}
**Renaming schema, tables, or columns will break Whalesync mappings**\
If you rename a table or column, you'll need to remap the impacted table/column in Whalesync. Note - remapping an impacted table will lead to duplicates unless you reset your data as well.
{% endhint %}
### **Handy Tips**
{% hint style="info" %}
**We support foreign keys (including two-way sync)!**\
Make sure to map both tables and reach out for help if not sure how to set it up.
{% endhint %}
{% hint style="info" %}
**Adding ".html" or "\_html" to the end of a column name will preserve HTML**\
If you name a Postgres column something such as "text\_html", Whalesync will preserve that column's values as HTML while syncing.
{% endhint %}