Automatically update a column on insert - ObjectionJS

Question

I want to automatically update the CreatedDateTime column whenever I want to insert or update column. But my problem is some tables have no CreatedDateTime column.

My code looks like this:

$beforeInsert(context) {
    this.CreatedDateTime = new Date().toISOString();
}

I tried explicitly specified the json schema like this:

static get jsonSchema() {
    return {
        type: 'object',
        properties: {
            CanteenFreeMealLineID: {
                type: 'integer',
            },
            CanteenFreeMealID: {
                type: 'integer',
            },
            DatacenterID: {
                type: 'integer',
            },
        },
    };
}

but it still forces to update to column CreatedDateTime