Create lowercase index

rubyonrails-talk
#1

Hi

I’m sorting some columns like this: MyModel.order(“LOWER(column) ASC”)… But these queries are quite slow. I’m on Postgres by the way.

Does Rails support creating a lowercase index for these situations? I know Postgres has support for it and I guess I can create one like this (found on SO):

execute "CREATE UNIQUE INDEX index_products_on_lower_name ON products USING btree (lower(name));"

But does Rails have support for creating it? Don’t like to use execute() if there is a better way :slight_smile:

Cheers,

Linus

#2

Not that I've ever seen but that's expected tbh.

#3

How about case insensetive collation for your columns?

#4

Direct from Rails4.0 ActiveRecord documentation:

Creating an index with a specific method
add_index(:developers, :name, using: 'btree')

generates:

CREATE INDEX index_developers_on_name ON developers USING btree (name) -- PostgreSQL
CREATE INDEX index_developers_on_name USING btree ON developers (name) -- MySQL

Note: only supported by PostgreSQL and MySQL

#5

I’m on Rails 3.2.13 I’m afraid.

I’ll just use the execute statement for now :slight_smile:

#6

That doesn’t address the lower(name) portion of the question, just the part where it specifies btree. Any idea how to do the lowercase portion?

#7

For PostgreSQL:

create index index_developers_on_name on developers((lower(name)));

Note the extra set of () to indicate that lower is a functional expression instead of a column name.