# Druid

> Prefer the Druid JDBC connection.

To add a database connection, click the **grid** icon in the top right, and navigate to **Admin** \> **Databases** \> **Add a database**.

## Edit connection details

Fill out the fields for that database, and click **Save changes** at the bottom. You can edit these settings at any time. Just remember to save your changes.

### Connection string

Paste a connection string here to pre-fill the remaining fields below.

### Display name

The display name for the database in the Metabase interface.

### Host

Your database’s IP address, or its domain name (e.g., esc.mydatabase.com).

### Broker node port

The database port (e.g, 8082).

### Use an SSH tunnel

See our [guide to SSH tunneling](/content/docs/latest/databases/ssh-tunnel/index.html).

### Allow unfolding of JSON columns

> Only available for the Druid JDBC connection.

This enables unfolding of JSON columns into their component fields.

See [JSON unfolding](/content/docs/latest/data-modeling/json-unfolding/index.html).

### Authentication

> Only available for the Druid JDBC connection.

Toggle on to enable basic authentication with a username and password.

### Re-run queries for simple explorations

Turn this option **OFF** if people want to click **Run** (the play button) before applying any [Summarize](/content/docs/latest/questions/query-builder/summarizing-and-grouping/index.html) or filter selections.

By default, Metabase will execute a query as soon as you choose an grouping option from the **Summarize** menu or a filter condition from the [drill-through menu](/content/learn/metabase-basics/querying-and-dashboards/questions/drill-through/index.html). If your database is slow, you may want to disable re-running to avoid loading data on each click.

### Choose when syncs and scans happen

See [syncs and scans](/content/docs/latest/databases/sync-scan#choose-when-syncs-and-scans-happen/index.html).

### Periodically refingerprint tables

> Periodic refingerprinting will increase the load on your database.

Turn this option **ON** to scan a sample of values every time Metabase runs a [sync](/content/docs/latest/databases/sync-scan#how-database-syncs-work/index.html).

A fingerprinting query examines the first 10,000 rows from each column and uses that data to guesstimate how many unique values each column has, what the minimum and maximum values are for numeric and timestamp columns, and so on. If you leave this option **OFF**, Metabase will only fingerprint your columns once during setup.

## Writable connection

Set up an additional connection used for write operations. See [Writable connections](/content/docs/latest/databases/writable-connection/index.html).

## Model features

There aren’t (yet) any model features available for Druid.

## Database routing

With database routing, an admin can build a question once using one database, and the question will run its query against a different database with the same schema depending on who is viewing the question.

See [Database routing](/content/docs/latest/permissions/database-routing/index.html).

## Danger zone

See [Danger Zone](/content/docs/latest/databases/danger-zone/index.html).