In Doctrine they suggest you write it as such:

```
@Column(type="string", options={"fixed" = true})
```

Thus, when a char type is detected, what it actually returns is a string with fixed = true.

See: http://www.doctrine-project.org/jira/browse/DDC-2807
http://doctrine-dbal.readthedocs.org/en/latest/reference/types.html#id84