> For the complete documentation index, see [llms.txt](https://docs.fastn.ai/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.fastn.ai/manage/database.md).
# Database
Which Postgres your workflows read and write through.
**Settings → Database**
The choice is exclusive and it is a redirect, not a migration, rows already written stay where they are.
Workflows can persist data with `fastn.db`. This page decides where that data lands.
> Which Postgres your workflows read and write through.
Every `fastn.db` call from this organisation goes to whichever option is selected here, and the page shows the active schema name in the form `ws_<32 hex characters>`.
### What a Developer sees
The page is read-only below Owner and Admin. A Developer gets the mode and the identifiers and nothing else:
| Row | Value |
| ------------------ | ----------------------------------------- |
| Mode | **Shared** |
| **DATABASE** | `fastn-managed` |
| **MANAGED SCHEMA** | `ws_`: your workspace's schema name |
Username, password and CA chain are not rendered for this role. That is deliberate, and it is enough: `fastn.db` connects for you, so a workflow never needs the credential. There is no table browser and no SQL console on this page: inspect data from a workflow.
### Two options
| | **Shared** (fastn runs it | **Your own**), you run it |
| ----------------- | ------------------------- | ------------------------- |
| **Backups** | fastn | You |
| **Capacity** | fastn | You |
| **Uptime** | fastn | You |
| **Network setup** | None | Allow our runners |
**Shared**: fastn runs it, and handles backups, patching, upgrades and capacity. Your workspace sits in its own schema, isolated from everyone else.
**Your own**: you run it: workflows connect to a Postgres you operate. You keep full control of the data and full responsibility for it, and you will need to allow fastn's runners through your network.
### Reasons to bring your own
Data residency requirements, a compliance regime that will not accept a processor's database, or an existing warehouse you want workflow data to land in directly.
If none of those apply, Shared is less work and one fewer thing to page you at 3am.
{% hint style="danger" %}
Switching changes where **new** reads and writes go. Rows are never copied between the two. If a workflow depends on data written before the switch, it will not find it. Migrate deliberately, or not at all.
{% endhint %}
### What the isolation actually is
**The unit of isolation is the workspace, not the customer.** Each workspace gets its own Postgres schema (the `ws_` above), isolated from every other workspace, which is what the page means by *your workspace sits in its own schema, isolated from everyone else*.
That is a boundary between you and other fastn customers. It is **not** a boundary between *your* customers: rows written on behalf of one of your customers and rows written on behalf of another land in the same schema. If you need per-customer separation inside it, build it: a customer column on every table, and a predicate on every query.
### Using it from a workflow
```javascript
await fastn.db.query(`
CREATE TABLE IF NOT EXISTS sync_log (
id SERIAL PRIMARY KEY,
customer_id TEXT,
source_id TEXT,
synced_at TIMESTAMP DEFAULT NOW()
)
`);
await fastn.db.query(
`INSERT INTO sync_log (customer_id, source_id) VALUES ($1, $2)`,
[customerId, record.id]
);
```
{% hint style="info" %}
The exact `fastn.db` call signature (whether it is `query(sql, params)` and whether parameters are `$1`-style), is worth confirming against a workflow's own **Docs** tab, which is generated from the runtime you are actually calling. See [Workflow runtime API](/reference/workflow-runtime.md).
{% endhint %}
---
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