{{ currentPost.title }}
{{ currentPost.datetime }}
{{ tagMap[tag].name }}
title rails migration中integer column的limit
description rails migration中integer column的limit
datetime 2014-11-13 10:05:47
tags rails_migration
category coding
link rails-migration-integer-column-limit
file 2014-11-13-100547-rails-migration-integer-column-limit
template post
end

integer的limit其實指的是byte的長度，而不是字串的長度，下面是對應表：

:limitSQL的資料型態大小最大值
1tinyint1 byte127
2smallint2 byte32767
3mediumint3 byte8388607
nil, 4, 11int(11)4 byte2147483647
5..8bigint8 byte9223372036854775807

Refs

Once and for all: Rails migrations integer :limit option