在 Rails 中，使用 mysql2 gem 从 MySQL 读取点类型时出现问题

Question

I'm working in a refactor from a legacy system and I'm having trouble with the "point" data type.

Inside Sequel Pro I can see the column "location" value as POINT(-22.81507676827597 -47.07767857976228)

But when I query it from the database

Mysql2::Client.new(
          host: ENV.fetch('LEGACY_DATABASE_HOST'),
          username: ENV.fetch('LEGACY_DATABASE_USERNAME'),
          password: ENV.fetch('LEGACY_DATABASE_PASSWORD'),
          database: ENV.fetch('LEGACY_DATABASE_NAME')
        ).query("SELECT * FROM local").first('location')

I get a weird result like "\\x00\\x00\\x00\\x00\\x01\\x01\\x00\\x00\\x00\\x84y\\xFF\\xDE\\xA8\\xD06\\xC0\\xE0\\xD6'_\\xF1\\x89G\\xC0", if I try to save it right away, it becomes a 0.

How is the proper way to deal with point data type in mysql with rails?

Answer 1

I strongly recommend that you use the activerecord-postgis-adapter gem, makes all this very simple. Although if you're set on doing it yourself, dig into that gem and see how they do the point stuff.