Rails migrations integer :limit option

migration_integer_limit_option

 literally always have to look up the meaning of :limit in migrations when it comes to integer values. Here's an overview. Now let's memorise it (oh, this works for MySQL, other databases may work differently):

:limit	    Numeric Type	Column Size	Max value
1	     tinyint	         1 byte	          127
2	     smallint	         2 bytes	32767
3	     mediumint	         3 byte	        8388607
nil, 4, 11    int(11)	         4 byte	       2147483647
5..8	      bigint	         8 byte	     9223372036854775807

Note: by default MySQL uses signed integers and Rails has no way (that I know of) to change this behaviour. Subsequently, the max. values noted are for signed integers.

taken from http://ariejan.net/2009/08/20/once-and-for-all-rails-migrations-integer-limit-option/

Also, Postgres doesn't support tinyint but Rails migrations handles that automatically and sets it to smallint.

Thanks for this gist. Really saved my bacon tonight!

Thanks for this important information 💯 👍

What's the default column size when :limit option is not specified?

What's the default column size when :limit option is not specified?

nvm. It's int(11) i.e. 4 bytes

thanks