Ruby/Rails - Active Record Db Migration to MySQL - Timestamp Type

Ruby/Rails - Active Record Db Migration to MySQL - timestamp type?

You can always insert a column with a custom type if you want. The symbol names are automatically converted into whatever ActiveRecord defines, but if you use a plain string it goes in as-is:

t.column :ar_timestamp, :timestamp
t.column :mysql_timestamp, 'timestamp'

What you get is ar_timestamp being the usual DATETIME type where mysql_timestamp is defined as TIMESTAMP.

Preventing Rails 4 migration from changing timestamp to datetime?

Well, As far as ActiveRecord is concerned timestamps == datetime. so when you call t.timestamp it created an column with type as datetime. AR doesn't seem to use MYSQL's TIMESTAMP datatype. here is the relavent source.

  def add_timestamps(table_name)
    add_column table_name, :created_at, :datetime
    add_column table_name, :updated_at, :datetime
  end

As you may note above, rails is creating two columns with datetime datatype instead of timestamp. so you will have explicitly specify the column type like this:

t.column, :timestamp, "column_name", limit: 6

Converting mysql column with type of datetime to time using Rails migration

Ensure you've run the migration.

Because, if the MySQL type is DATETIME of TIMESTAMP, Rails represents is DateTime. But for DATE and TIME, Rails represents it as-is: Date and Time. Only for the DATETIME/TIMESTAMP does Rails take an auto-decision for us. For the rest, it maintains as-is.

Rails' datetime and timestamp in a migration file are the same for MySQL and Sqlite3?

I would recommend using the :datetime, because so it's clear what to use. I believe rails is using DATETIME for both in the DB is because of the Problem that the datetimes representable with the unix timestamp or the MySQL TIMESTAMP field. Since timestamp is by default a 32bit Integer (see Wikipedia:Timestamp) it can only represent dates between 1901-12-13 (or 1970-01-01 if no negative values are allowed like in MySQL) and 2038-01-19. After or before that it will overflow. This is the year 2038 problem.

So to make it clear to everybody I would name it :datetime in the migration.

The TIMESTAMP data type has a range of '1970-01-01 00:00:01' UTC to '2038-01-19 03:14:07' UTC. It has varying properties, depending on the MySQL version and the SQL mode the server is running in. These properties are described later in this section. Source

Change a column type from Date to DateTime during ROR migration

First in your terminal:

rails g migration change_date_format_in_my_table

Then in your migration file:

For Rails >= 3.2:

class ChangeDateFormatInMyTable < ActiveRecord::Migration
  def up
    change_column :my_table, :my_column, :datetime
  end

  def down
    change_column :my_table, :my_column, :date
  end
end

ActiveRecord DATETIME column values in mysql

It seems like there is no way built in to Rails to get around casting that date to something non-nil.

The fact that there is no way around this is a sign that you're probably doing something in a non-optimal way, so my first suggestion is to just migrate all 0000-00-00 00:00:00 values to nil if you can.

If that isn't an option. You can find out whether any one record has 0000-00-00 00:00:00 via sql conditions something like this:

Post.where("date_field = '0000-00-00 00:00:00' && id = ?", post.id).exists?

Hope that helps.

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