Adding foreign key to exisiting table

I would like to be able to add foreign key to an already existing table. We are working on an application and the database is likely to change over time. The only issue is altering an exisiting table. We would have used another framework but have decided to stick with codeigniter4 due to its performance.

Like this?
https://codeigniter4.github.io/userguide...reign-keys

You can use $db->query().
See https://codeigniter4.github.io/userguide...ar-queries

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This feature is added in v4.3.0.
See https://codeigniter4.github.io/userguide...html#forge
Forge::processIndexes()

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