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

# MariaDB Route

> Store MQTT data in MariaDB with automatic query execution and MySQL compatibility

## MariaDB Overview

The `MARIADB` route stores MQTT messages in MariaDB databases. MariaDB is a MySQL-compatible database with enhanced features and performance optimizations.

<Note>
  MariaDB offers drop-in MySQL compatibility with additional features like improved replication and storage engines. Use the same configuration as MySQL with the `MARIADB` route type.
</Note>

## Basic Syntax

```lot theme={null}
DEFINE ROUTE SensorDB WITH TYPE MARIADB
    ADD SQL_CONFIG
        WITH SERVER "mariadb.example.com"
        WITH PORT '3306'
        WITH DATABASE "iot_data"
        WITH USERNAME "iot_user"
        WITH PASSWORD "secure_password"
    ADD EVENT StoreSensorReading
        WITH SOURCE_TOPIC "sensors/+/reading"
        WITH QUERY "INSERT INTO readings (ts, sensor_id, value) VALUES (NOW(), '{sensor_id}', '{value.json}')"
```

***

## Connection Configuration

### SQL\_CONFIG Parameters

<ParamField path="SERVER" type="string" required>
  MariaDB server hostname or IP address.
</ParamField>

<ParamField path="DATABASE" type="string" required>
  Target database name.
</ParamField>

<ParamField path="USERNAME" type="string" required>
  Database username.
</ParamField>

<ParamField path="PASSWORD" type="string" required>
  Database password.
</ParamField>

<AccordionGroup>
  <Accordion title="Optional Settings">
    <ParamField path="PORT" type="integer">
      MariaDB port. Default: 3306.
    </ParamField>

    <ParamField path="USE_SSL" type="boolean">
      Enable SSL connection. Default: false.
    </ParamField>
  </Accordion>
</AccordionGroup>

<Warning>
  **Never hardcode credentials in production.** Use environment variables and encrypted secrets to keep sensitive values out of your route definitions:

  ```lot theme={null}
  WITH SERVER GET ENV "DB_HOST"
  WITH USERNAME GET ENV "DB_USER"
  WITH PASSWORD GET SECRET "DB_PASSWORD"
  ```

  See [Environment Variables & Secrets](/mqtt-broker/secrets-and-env) for setup and usage.
</Warning>

***

## Writing Data

<Tabs>
  <Tab title="Basic Storage">
    Store sensor data in MariaDB:

    ```lot theme={null}
    DEFINE ROUTE SensorStorage WITH TYPE MARIADB
        ADD SQL_CONFIG
            WITH SERVER "mariadb.example.com"
            WITH PORT '3306'
            WITH DATABASE "iot_data"
            WITH USERNAME "iot_user"
            WITH PASSWORD "secure_password"
        ADD EVENT StoreReading
            WITH SOURCE_TOPIC "sensors/#"
            WITH QUERY "INSERT INTO sensor_data (timestamp, topic, payload) VALUES (NOW(), '{source_topic}', '{value.json}')"
    ```
  </Tab>

  <Tab title="With SSL">
    Secure connection:

    ```lot theme={null}
    DEFINE ROUTE SecureStorage WITH TYPE MARIADB
        ADD SQL_CONFIG
            WITH SERVER "mariadb.cloud.com"
            WITH PORT '3306'
            WITH DATABASE "production"
            WITH USERNAME "app_user"
            WITH PASSWORD "secure_password"
            WITH USE_SSL "true"
        ADD EVENT StoreEvent
            WITH SOURCE_TOPIC "events/#"
            WITH QUERY "INSERT INTO events (ts, topic, data) VALUES (NOW(), '{source_topic}', '{value.json}')"
    ```
  </Tab>

  <Tab title="UPSERT">
    Insert a record or update it if a duplicate key exists. MariaDB supports both `ON DUPLICATE KEY UPDATE` (MySQL-compatible) and `ON CONFLICT` (PostgreSQL-compatible in newer versions):

    ```lot theme={null}
    DEFINE ROUTE DeviceRegistry WITH TYPE MARIADB
        ADD SQL_CONFIG
            WITH SERVER "mariadb.example.com"
            WITH PORT '3306'
            WITH DATABASE "iot_data"
            WITH USERNAME "iot_user"
            WITH PASSWORD "secure_password"
        ADD EVENT RegisterDevice
            WITH SOURCE_TOPIC "devices/+/registered"
            WITH QUERY "INSERT INTO devices (device_id, name, area, active, updated_at) VALUES ('{value.json.device_id}', '{value.json.name}', '{value.json.area}', 1, NOW()) ON DUPLICATE KEY UPDATE name = VALUES(name), area = VALUES(area), updated_at = NOW()"
    ```
  </Tab>

  <Tab title="UPDATE">
    Modify existing records when a status change arrives:

    ```lot theme={null}
    DEFINE ROUTE DeviceRegistry WITH TYPE MARIADB
        ADD SQL_CONFIG
            WITH SERVER "mariadb.example.com"
            WITH PORT '3306'
            WITH DATABASE "iot_data"
            WITH USERNAME "iot_user"
            WITH PASSWORD "secure_password"
        ADD EVENT UpdateDeviceStatus
            WITH SOURCE_TOPIC "devices/+/status"
            WITH QUERY "UPDATE devices SET current_status = '{value.json.status}', last_seen = NOW() WHERE device_id = '{value.json.device_id}'"
    ```
  </Tab>

  <Tab title="DELETE">
    Remove records on a decommission or cleanup event:

    ```lot theme={null}
    DEFINE ROUTE DeviceRegistry WITH TYPE MARIADB
        ADD SQL_CONFIG
            WITH SERVER "mariadb.example.com"
            WITH PORT '3306'
            WITH DATABASE "iot_data"
            WITH USERNAME "iot_user"
            WITH PASSWORD "secure_password"
        ADD EVENT DecommissionDevice
            WITH SOURCE_TOPIC "devices/+/decommissioned"
            WITH QUERY "DELETE FROM devices WHERE device_id = '{value.json.device_id}' AND active = 0"
    ```
  </Tab>
</Tabs>

<Info>
  **Alternative: STORE IN with Models** — Instead of writing EVENT queries, you can bind a [model](/lot-language/models/overview) directly to this route. Every `PUBLISH MODEL` call automatically inserts a row — no query needed:

  ```lot theme={null}
  DEFINE MODEL SensorReading
      ADD STRING "sensor_id"
      ADD DOUBLE "value"
      STORE IN "SensorStorage"
          WITH TABLE "sensor_data"
  ```

  See [Data Storage Overview](./overview#with-models-store-in) for the full STORE IN workflow.
</Info>

***

## Reading Data

EVENTs also support SELECT queries to read data back from the database. Publish a message to the event's `SOURCE_TOPIC`, and the query result is published to `DESTINATION_TOPIC`:

```lot theme={null}
DEFINE ROUTE SensorDB WITH TYPE MARIADB
    ADD SQL_CONFIG
        WITH SERVER "mariadb.example.com"
        WITH PORT '3306'
        WITH DATABASE "iot_data"
        WITH USERNAME "iot_user"
        WITH PASSWORD "secure_password"
    ADD EVENT GetLatestReading
        WITH SOURCE_TOPIC "db/query/latest"
        WITH DESTINATION_TOPIC "db/result/latest"
        WITH QUERY "SELECT sensor_id, value FROM sensor_data WHERE sensor_id = '{payload}' ORDER BY timestamp DESC LIMIT 1"
```

To trigger this query, publish the sensor ID to the source topic:

```
Topic:   db/query/latest
Payload: temp001
```

The query result is published to `db/result/latest`, where your actions or external clients can consume it.

### Timed Polling

EVENTs can also run SELECT queries on a fixed schedule using `WITH EVERY`:

```lot theme={null}
DEFINE ROUTE DeviceRegistry WITH TYPE MARIADB
    ADD SQL_CONFIG
        WITH SERVER "mariadb.example.com"
        WITH PORT '3306'
        WITH DATABASE "iot_data"
        WITH USERNAME "iot_user"
        WITH PASSWORD "secure_password"
    ADD EVENT PollActiveDevices
        WITH EVERY 10 SECONDS
        WITH DESTINATION_TOPIC "dashboard/devices/active"
        WITH QUERY "SELECT device_id, name, current_status, last_seen FROM devices WHERE active = 1 ORDER BY name"
```

***

## Troubleshooting

<AccordionGroup>
  <Accordion title="Connection Refused">
    * Verify SERVER and PORT are correct
    * Check MariaDB is running and accepting connections
    * Verify firewall allows connections on port 3306
  </Accordion>

  <Accordion title="Authentication Failed">
    * Verify USERNAME and PASSWORD are correct
    * Check user has permissions on the DATABASE
    * Verify user can connect from your host
  </Accordion>
</AccordionGroup>

***

## Next Steps

<CardGroup cols={2}>
  <Card title="Data Storage Routes Overview" icon="database" href="./overview">
    Compare all storage options.
  </Card>

  <Card title="SQL Server Route" icon="microsoft" href="./sqlserver">
    Configure Microsoft SQL Server storage.
  </Card>
</CardGroup>