I am designing a database and have the two following tables:

* `t_model` (with fields: `model_id` (PK), `model_name`)
* `t_model_version` (with fields: `model_id` (PK, FK), `model_version` (PK), `start_validity_date`, `end_validity_date`)

As one can see, `t_model_version` its PK is a composite PK. One of the fields part of the PK is also a FK (the PK of `t_model`). I was wondering whether this is good or bad practice? I would like to avoid getting into difficulties later on that I cannot yet foresee...

`t_model` holds different models (e.g. different models/functional forms to predict macroeconomic growth). `t_model_version` holds the version numbers per model (e.g. a different version of a model means that the functional form is kept but that the coefficient estimates have been updated).

*Edit:* My question is not about **how** to add a FK when the field of interest is already part of a composite PK, but whether this a good practice. Hence, my question is not a duplication of [Composite Primary Key + Foreign Key](https://stackoverflow.com/questions/11215494/composite-primary-key-foreign-key).