> For the complete documentation index, see [llms.txt](https://docs.cybus.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.cybus.io/2-4-2/guides/system-connectivity/databases-time-series-storage/postgresql-integration.md).

# PostgreSQL Integration

This guide describes how to integrate PostgreSQL with Connectware. You configure a service commissioning file that writes shop floor data into a PostgreSQL table and polls query results back into an MQTT topic. A complete example file is available at the end of this guide.

## Objectives

* Establishing a connection between Connectware and PostgreSQL.
* Writing shop floor data from an ISA-95-style topic hierarchy into a production events table.
* Polling recent rows from the database into an MQTT topic on a fixed interval.

## Prerequisites

To follow this guide, you will need the following:

* A running instance of Cybus Connectware.
* A PostgreSQL server that is reachable from Connectware.
* A database role with `INSERT` and `SELECT` privileges on the target database.
* Access to the [Admin UI](/2-4-2/access/admin-ui.md) with sufficient [user permissions](/2-4-2/access/user-management.md).
* Basic knowledge of MQTT and the Connectware [services](/2-4-2/data-flows/services.md) concept (for example, [service commissioning files](/2-4-2/data-flows/service-commissioning-files.md), [connections](/2-4-2/data-flows/service-commissioning-files/resources/cybus-connection.md), and [endpoints](/2-4-2/data-flows/service-commissioning-files/resources/cybus-endpoint.md)).

## Connectware and PostgreSQL Integration

Connectware communicates with PostgreSQL through the [SQL connector](/2-4-2/connectors/enterprise-connectors/sql.md). The connector works by defining SQL queries or query templates on endpoints:

* **Write endpoints** define a query template, typically an `INSERT` statement. The template contains placeholders in the form `$identifier`, which the connector replaces with the values from the JSON payload of each incoming MQTT message (see [Placeholder Syntax](/2-4-2/connectors/enterprise-connectors/sql.md#placeholder-syntax)).
* **Subscribe endpoints** define a query and a polling interval. The connector executes the query on a regular basis and publishes the result rows as a JSON array to the MQTT broker.

The same connector also serves MariaDB databases; only the URL scheme in the connection changes.

The MQTT topics in this guide follow an ISA-95-style equipment hierarchy (`<enterprise>/<site>/<area>/<line>/<cell>`). The mapping subscribes with named wildcards across all levels, so any machine in the hierarchy is picked up without changing the integration, and the topic levels become column values in the database.

### Production Events Table

The integration writes into a single table that stores one row per shop floor event. Create it in your target database:

{% code lineNumbers="true" %}

```sql
CREATE TABLE production_events (
  id bigint GENERATED ALWAYS AS IDENTITY PRIMARY KEY,
  event_time timestamptz NOT NULL DEFAULT now(),
  site text NOT NULL,
  area text NOT NULL,
  line text NOT NULL,
  cell text NOT NULL,
  event_type text NOT NULL,
  event_value double precision NOT NULL
);
```

{% endcode %}

The `event_time` column defaults to the insert time, stored as [timestamp with time zone](https://www.postgresql.org/docs/current/datatype-datetime.html), so the messages do not need to carry a timestamp. If you want to store machine timestamps instead, add a column for them and extend the `INSERT` statement with another placeholder.

### PostgreSQL Connection Properties

We add the connection values as parameters to the service commissioning file, so you can set them when you install the service.

Do not worry about copying the service commissioning file snippets together into one, the complete example file is available at the end of this guide.

* `postgresHost` and `postgresPort`: The hostname and port of your PostgreSQL server. The default port is `5432`.
* `postgresUsername` and `postgresPassword`: The database role that Connectware uses to connect.
* `postgresDatabase`: The database that contains the `production_events` table.
* `pollingInterval`: The interval in milliseconds between polling queries.
* `topicRoot`: The root of the MQTT topic hierarchy. Defaults to `enterprise`.

{% code lineNumbers="true" %}

```yaml
parameters:
  postgresHost:
    description: Hostname or IP address of the PostgreSQL server
    type: string
    default: example.com

  postgresPort:
    description: Port of the PostgreSQL server
    type: integer
    default: 5432

  postgresUsername:
    description: Database role that Connectware uses to connect
    type: string
    default: connectware

  postgresPassword:
    description: Password of the database role
    type: string

  postgresDatabase:
    description: Database that contains the production_events table
    type: string
    default: factory

  pollingInterval:
    description: Interval in milliseconds between polling queries
    type: integer
    default: 10000

  topicRoot:
    description: Root of the MQTT topic hierarchy
    type: string
    default: enterprise
```

{% endcode %}

### PostgreSQL Connection

To connect to the database, we set up a `Cybus::Connection` resource that uses the SQL connector. The connector expects a single connection URL of the form `postgres://<user>:<password>@<host>:<port>/<database>`, which the `!sub` substitution assembles from the parameters. All endpoints in this guide share this connection.

{% code lineNumbers="true" %}

```yaml
resources:
  postgresConnection:
    type: Cybus::Connection
    properties:
      protocol: Sql
      connection:
        url: !sub 'postgres://${postgresUsername}:${postgresPassword}@${postgresHost}:${postgresPort}/${postgresDatabase}'
```

{% endcode %}

For all available connection properties, including certificate handling and the reconnection strategy, see [SQL Connection Properties](/2-4-2/connectors/enterprise-connectors/sql/sqlconnection.md).

### Writing Production Events

The write endpoint defines the `INSERT` statement as a query template. Each placeholder, for example `$site`, is replaced with the value of the matching key in the JSON payload of the incoming message.

The mapping feeds the endpoint from the topic hierarchy. It uses [named wildcards](/2-4-2/data-flows/service-commissioning-files/resources/cybus-mapping.md#wildcards), so the topic levels are available in the `$context.vars` object of the `transform` rule. The rule builds one flat object whose keys match the query placeholders, combining the topic levels with the `event_type` and `value` fields of the machine payload.

{% code lineNumbers="true" %}

```yaml
productionEventWrite:
  type: Cybus::Endpoint
  properties:
    protocol: Sql
    connection: !ref postgresConnection
    write:
      query: >-
        INSERT INTO production_events
        (site, area, line, cell, event_type, event_value)
        VALUES ($site, $area, $line, $cell, $event_type, $event_value)

productionEventMapping:
  type: Cybus::Mapping
  properties:
    mappings:
      - subscribe:
          topic: !sub '${topicRoot}/+site/+area/+line/+cell/production-events'
        publish:
          endpoint: !ref productionEventWrite
        rules:
          - transform:
              expression: >-
                {
                  "site": $context.vars.site,
                  "area": $context.vars.area,
                  "line": $context.vars.line,
                  "cell": $context.vars.cell,
                  "event_type": event_type,
                  "event_value": value
                }
```

{% endcode %}

Any message published to a matching topic, for example `enterprise/hamburg/assembly/line-1/press-01/production-events`, now inserts one row into the table. The machine payload only needs the event fields, the topic provides the rest:

{% code lineNumbers="true" %}

```json
{
  "event_type": "temperature",
  "value": 42.1
}
```

{% endcode %}

All placeholders defined in the query must exist in the resulting message payload. If one is missing, the connector logs an error and ignores the message (see [Writing Data](/2-4-2/connectors/enterprise-connectors/sql.md#writing-data)).

{% hint style="warning" %}
The SQL connection on the Connectware side does not perform any data validation against the database schema. The senders of the MQTT messages must ensure that the values match the column types, for example a number for the `event_value` column.
{% endhint %}

### Polling Recent Production Events

For the opposite direction, a subscribe endpoint executes a query on a fixed interval and publishes the result rows to the MQTT broker. This example reads the production events of the last five minutes, so downstream consumers such as dashboards or MES systems receive a regularly updated snapshot.

{% code lineNumbers="true" %}

```yaml
recentEventsQuery:
  type: Cybus::Endpoint
  properties:
    protocol: Sql
    connection: !ref postgresConnection
    subscribe:
      query: >-
        SELECT id, event_time, site, area, line, cell,
        event_type, event_value
        FROM production_events
        WHERE event_time > now() - interval '5 minutes'
        ORDER BY event_time DESC
        LIMIT 50
      interval: !ref pollingInterval

recentEventsMapping:
  type: Cybus::Mapping
  properties:
    mappings:
      - subscribe:
          endpoint: !ref recentEventsQuery
        publish:
          topic: !sub '${topicRoot}/production-events/recent'
```

{% endcode %}

Choose the polling interval carefully. A low value can overload the database. Instead of a fixed interval, you can also poll on a schedule with the `cronExpression` property (see [SQL Endpoint Properties](/2-4-2/connectors/enterprise-connectors/sql/sqlendpoint.md)).

Every query execution publishes a message with a `timestamp` property and a `value` property that contains the result rows. If the query returns no rows, `value` is an empty array (`[]`).

{% code lineNumbers="true" %}

```json
{
  "timestamp": 1768560000000,
  "value": [
    {
      "id": 1,
      "event_time": "2026-01-16T10:40:00.000Z",
      "site": "hamburg",
      "area": "assembly",
      "line": "line-1",
      "cell": "press-01",
      "event_type": "temperature",
      "event_value": 42.1
    }
  ]
}
```

{% endcode %}

## Verifying the Integration

1. Install the service and set the parameters with the values of your PostgreSQL server.
2. Check that the connection is in the **Connected** state on the service details page in the Admin UI. If the credentials or the database name are wrong, the connection does not reach the connected state.
3. Publish a test message with the machine payload shown in this guide to `enterprise/hamburg/assembly/line-1/press-01/production-events`, for example with an MQTT client or the Admin UI.
4. Check that the row arrived in the database, for example with `SELECT * FROM production_events ORDER BY id DESC LIMIT 10` in [psql](https://www.postgresql.org/docs/current/app-psql.html). The result of every write is also published to the `/res` topic of the write endpoint, with `value` set to `true` on success.
5. Use the [Data Explorer](/2-4-2/monitoring/data-explorer.md) to inspect the polled result rows on the `enterprise/production-events/recent` topic.

## Service Commissioning File Example

{% file src="/files/pxGbAvpw3OF8hj5xq8Q7" %}

{% code title="postgresql-example.yml" lineNumbers="true" expandable="true" %}

```yaml
---
# ----------------------------------------------------------------------------
# Service Commissioning File
# ----------------------------------------------------------------------------
# Copyright: Cybus GmbH
# Contact: support@cybus.io
# ----------------------------------------------------------------------------
# PostgreSQL Integration (Example)
# ----------------------------------------------------------------------------

description: >
  Service commissioning file for the integration between Connectware and
  PostgreSQL (Example)

metadata:
  name: PostgreSQL Integration
  provider: cybus
  homepage: https://www.cybus.io
  version: 1.0.0

parameters:
  postgresHost:
    description: Hostname or IP address of the PostgreSQL server
    type: string
    default: example.com

  postgresPort:
    description: Port of the PostgreSQL server
    type: integer
    default: 5432

  postgresUsername:
    description: Database role that Connectware uses to connect
    type: string
    default: connectware

  postgresPassword:
    description: Password of the database role
    type: string

  postgresDatabase:
    description: Database that contains the production_events table
    type: string
    default: factory

  pollingInterval:
    description: Interval in milliseconds between polling queries
    type: integer
    default: 10000

  topicRoot:
    description: Root of the MQTT topic hierarchy
    type: string
    default: enterprise

resources:
  # Connection to the PostgreSQL database
  postgresConnection:
    type: Cybus::Connection
    properties:
      protocol: Sql
      connection:
        url: !sub 'postgres://${postgresUsername}:${postgresPassword}@${postgresHost}:${postgresPort}/${postgresDatabase}'

  # Inserts one row into the production_events table per message
  productionEventWrite:
    type: Cybus::Endpoint
    properties:
      protocol: Sql
      connection: !ref postgresConnection
      write:
        query: >-
          INSERT INTO production_events
          (site, area, line, cell, event_type, event_value)
          VALUES ($site, $area, $line, $cell, $event_type, $event_value)

  # Feeds the write endpoint from the ISA-95 topic hierarchy. The named
  # wildcards provide the topic levels in $context.vars, so the transform
  # rule can build one flat object whose keys match the query placeholders.
  productionEventMapping:
    type: Cybus::Mapping
    properties:
      mappings:
        - subscribe:
            topic: !sub '${topicRoot}/+site/+area/+line/+cell/production-events'
          publish:
            endpoint: !ref productionEventWrite
          rules:
            - transform:
                expression: >-
                  {
                    "site": $context.vars.site,
                    "area": $context.vars.area,
                    "line": $context.vars.line,
                    "cell": $context.vars.cell,
                    "event_type": event_type,
                    "event_value": value
                  }

  # Polls the production events of the last five minutes
  recentEventsQuery:
    type: Cybus::Endpoint
    properties:
      protocol: Sql
      connection: !ref postgresConnection
      subscribe:
        query: >-
          SELECT id, event_time, site, area, line, cell,
          event_type, event_value
          FROM production_events
          WHERE event_time > now() - interval '5 minutes'
          ORDER BY event_time DESC
          LIMIT 50
        # Be careful with low values, they can overload the database
        # (the unit is milliseconds).
        interval: !ref pollingInterval

  recentEventsMapping:
    type: Cybus::Mapping
    properties:
      mappings:
        - subscribe:
            endpoint: !ref recentEventsQuery
          publish:
            topic: !sub '${topicRoot}/production-events/recent'
```

{% endcode %}


---

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