mysql key too long error

rubyonrails-talk
1

I'm using the acts as taggable on plugin, and in the migrations there's a line of code to create an index:

add_index :taggings, [:taggable_id, :taggable_type, :context], :name => "tagging_index", :limit => {:name => 10, :surname => 20}

When I use unicode, the migration fails and I get told that the index is too long and can only be 1000 bytes. I switched over to ascii to see if I get the same problem and I didn't. I really want to use unicode, so I want to get this working.

I'm running Rails 3.0.7 with MySQL 5.1.

2

I'm using the acts as taggable on plugin, and in the migrations there's a line of code to create an index:

add_index :taggings, [:taggable_id, :taggable_type, :context], :name => "tagging_index", :limit => {:name => 10, :surname => 20}

When I use unicode, the migration fails and I get told that the index is too long and can only be 1000 bytes. I switched over to ascii to see if I get the same problem and I didn't. I really want to use unicode, so I want to get this working.

If you want to limit the length of the prefix used for indexes, you'll need to change name/surname up there for the string columns you want to index (ie taggable_type and context) and change the numbers as appropriate to your data

Fred

3

How can I use the :limit to change taggable_ type and context?

4

How can I use the :limit to change taggable_ type and context?

The limit tells mysql how much of the column to use for the index. Pick values such that your total index length falls within the limit (you're probably better off picking a smaller value for taggable_type, you're very unlikely to have massively long values in that column)

Fred

5

Oh, I was looking for an example of how to use it like a piece of code or something.

6

Nevermind, I got it. I just have to test to see if it works. Thanks for your help!