Migrations - Creating 2 tables in the up function

migrations-creating-2-tables.js

exports.up = function(knex, Promise) {
  return knex.schema
    .createTable('farms', tbl => {
      tbl.increments();
      tbl.string('farm_name', 128)
        .notNullable();
    })
    // we can chain together createTable
    .createTable('ranchers', tbl => {
      tbl.increments();
      tbl.string('rancher_name', 128);
      tbl.integer('farm_id')
        // forces integer to be positive
        .unsigned()
        .notNullable()
        .references('id')
        // this table must exist already
        .inTable('farms')
    })
};



// Note that the foreign key can only be created after the reference table.

// In the down function, the opposite is true. We always want 
// to drop a table with a foreign key before dropping the table it references.



exports.down = function(knex, Promise) {
    // drop tables in opposite order 
  // than they were created (shoes & socks concept)
  return knex.schema
    .dropTableIfExists('ranchers')
    .dropTableIfExists('farms')
};