As mentioned earlier, you should not be thinking about database and tables at all while working with content models.
It is not the right solution to alter anything on DB layer.
Think in terms of types, aspects, properties associations etc. A type approximates a table, the node approximates a row, and the property approximates a column.
You can define types, aspects and properties and apply to a node. If your requirement is that you frequently apply some properties. Define an aspect and add the properties in it and apply aspect to nodes. You can remove the aspect at any point of time based on need/code logic etc.
Later, you can choose to remove the aspect definition from content model if that is required and those properties are no longer valid for re-use. If you have requirement to re-use the same properties then leave them in content model.