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

# MySQL Database Configuration

This section documents the supported MySQL configuration.

### Database Schema

The engine's MySQL database schema does not support milliseconds precision for the column types `TIMESTAMP` and `DATETIME`:
I.e., a to be stored value is rounded to the next or previous second, e.g., `2021-01-01 15:00:46.731` is rounded to `2021-01-01 15:00:47`.

<Info>
  **Heads Up!**

  The missing millisecond’s precision for date/time values impacts the process engine's behavior.
  Please read [how to configure the MySQL JDBC Driver](#jdbc-driver-configuration)
  to ensure that date/time values are handled correctly.
</Info>

### JDBC Driver Configuration

Here you can find the MySQL JDBC Driver’s configuration prerequisites to ensure a frictionless behavior
of the process engine.

#### Disable sending milliseconds for date/time values

<Info>
  **Heads Up!**

  This configuration flag is mandatory to avoid unexpected behavior when operating the process engine with MySQL.
</Info>

When sending a date/time value as part of any SQL statement to the database, the MySQL JDBC Driver >= 5.1.23 sends milliseconds.
This behavior is problematic since the engine's MySQL database [schema does not support milliseconds precision for date/time values][mysql-schema-milliseconds].

To ensure correct behavior of the process engine when sending date/time values, make sure to update your MySQL JDBC Driver to a version >= 5.1.37.
You can avoid sending milliseconds to the MySQL Server in these versions by setting [`sendFractionalSeconds=false`][mysql-fract-secs]
in your JDBC connection URL.

Please find below examples of unwanted behavior that occurs, in case the flag `sendFractionalSeconds=false` is not provided:

* When a user performs a task query with `due date == 2021-01-01 15:00:46.731`, the query returns
  results equal to `2021-01-01 15:00:46.731`. However, since the engine's [database schema does not store
  milliseconds][mysql-schema-milliseconds], no result is returned.
* When a user sets a due date to a task, the value is rounded to the next or previous second,
  e.g., `2021-01-01 15:00:46.731` is rounded to `2021-01-01 15:00:47`. Please also see the official [MySQL documentation](https://dev.mysql.com/doc/refman/5.6/en/fractional-seconds.html).

[mysql-schema-milliseconds]: #database-schema

[mysql-fract-secs]: https://dev.mysql.com/doc/connector-j/8.0/en/connector-j-connp-props-datetime-types-processing.html#cj-conn-prop_sendFractionalSeconds