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

# MySQL destination

> Configure a MySQL destination, prepare the target table, and verify Upsert delivery.

MySQL is available as a destination connector. MantrixFlow validates the target
contract, then delivers only the published SQL model's columns into the
configured table.

## Destination contract

The final MySQL table must exist before delivery begins. Create it with the
explicit setup action in the destination editor when available, or run reviewed
DDL in MySQL yourself. The delivery runner does not create final tables.

The table should:

* use InnoDB;
* use `utf8mb4` for general text;
* contain every column selected by the published SQL model;
* use compatible types; and
* define a primary or unique key for deterministic Upsert behavior.

## Required destination access

Create a dedicated writer. If table creation is managed separately, the runtime
user needs only data access to existing tables.

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
CREATE DATABASE IF NOT EXISTS analytics
  CHARACTER SET utf8mb4
  COLLATE utf8mb4_unicode_ci;

CREATE USER 'mantrixflow_writer'@'%'
  IDENTIFIED BY 'replace-with-a-secret';

GRANT SELECT, INSERT, UPDATE
  ON analytics.*
  TO 'mantrixflow_writer'@'%';

FLUSH PRIVILEGES;
```

Grant `CREATE` and `ALTER` only to a separate setup user or when your operating
policy explicitly allows the app's setup action to reconcile tables.

## Connection fields

| Field           | Notes                                                 |
| --------------- | ----------------------------------------------------- |
| Connection Name | Descriptive workspace name, such as `Analytics MySQL` |
| Host            | MySQL hostname or provider endpoint                   |
| Port            | Usually `3306`                                        |
| Database        | Database containing destination tables                |
| Username        | Dedicated destination user                            |
| Password        | Destination user password                             |
| SSL Mode        | Use the encrypted mode required by the provider       |

## Create the connection

1. Open **Connections**.
2. Click **+ New Connection**.
3. Set the role to **Destination**.
4. Choose **MySQL**.
5. Complete the connection fields.
6. Click **Test Connection**.
7. Save after the test succeeds.

## Prepare a destination table

This example accepts customer rows from Airtable or another source:

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
CREATE TABLE analytics.airtable_customers (
  external_id varchar(64) NOT NULL,
  name varchar(255),
  email varchar(320),
  source_created_at datetime(6),
  synced_at timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
  PRIMARY KEY (external_id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
```

The SQL model must output `external_id`, `name`, `email`, and
`source_created_at`. Columns with database defaults, such as `synced_at`, can be
omitted when the table permits it.

## Configure delivery

1. Open **Destinations** and click **Add destination**.
2. Choose the MySQL connection, target database, and save.
3. Open **Transformations**, select that destination, and create the SQL model.
4. Save, validate, preview, and publish the revision.
5. Return to the destination editor and, under **Published output targets**,
   enter `database.table`, for example `analytics.airtable_customers`.
6. Choose the stable primary or unique key as the Upsert key.
7. Create/verify the table when needed and save the destination.

## Upsert behavior

With a primary or unique key, a first run inserts rows and later runs update the
matching rows. This is the recommended production configuration.

Without a key, delivery cannot identify an existing row deterministically.
Add a stable primary or unique key before enabling repeated runs.

## Verify delivery

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
SELECT COUNT(*) AS delivered_rows
FROM analytics.airtable_customers;

SELECT external_id, COUNT(*) AS occurrences
FROM analytics.airtable_customers
GROUP BY external_id
HAVING COUNT(*) > 1;

SELECT external_id, name, email, source_created_at
FROM analytics.airtable_customers
ORDER BY external_id
LIMIT 25;
```

The duplicate query should return no rows. Compare the count with the run's
**rows written** value, accounting for any SQL filters.

Confirm that no internal loader tables were written into the destination:

```sql theme={"theme":{"light":"github-light","dark":"github-dark"}}
SELECT TABLE_NAME
FROM information_schema.TABLES
WHERE TABLE_SCHEMA = 'analytics'
  AND TABLE_NAME LIKE '\\_dlt\\_%';
```

## Troubleshooting

| Error                            | Resolution                                                                 |
| -------------------------------- | -------------------------------------------------------------------------- |
| Destination table does not exist | Create the exact `database.table` before running, then validate again.     |
| Column is missing                | Add the column to the table or remove it from the published SQL output.    |
| Access denied                    | Grant `SELECT`, `INSERT`, and `UPDATE` on the destination database.        |
| Data too long                    | Increase `VARCHAR` length, use `TEXT`, or trim intentionally in SQL.       |
| Incorrect decimal value          | Align precision and scale between SQL output and MySQL.                    |
| Incorrect datetime value         | Emit a valid timestamp and handle null or zero dates before delivery.      |
| Duplicate-key failure            | Confirm the selected Upsert key matches the table's primary or unique key. |
| TLS connection failure           | Use the provider-required SSL mode and network endpoint.                   |

Follow the [Airtable and MySQL pipeline guide](/example/pipelines/airtable-and-mysql)
for complete Airtable-to-MySQL and MySQL-to-Airtable examples.