The supported solution would be to change the metadata values through the LF Client or Workflow.

One problem in dealing with the SQL database is that a minor mistake or oversight could end up doing a lot of damage to your repository, and metadata is more complex than just one value in one column in one table.

What exactly are you trying to accomplish?

There's also an SDK so you can write your own custom application if the Laserfiche clients don't provide the functionality you need.

Like Jason said above, it would help if we knew what the end goal is.