Difference between string and text in rails?

Question

I'm making a new web app using Rails, and was wondering, what's the difference between string and text? And when should each be used?

Answer 1

The difference relies in how the symbol is converted into its respective column type in query language.

with MySQL :string is mapped to VARCHAR(255)

• https://edgeguides.rubyonrails.org/active_record_migrations.html

:string |                   VARCHAR                | :limit => 1 to 255 (default = 255)   :text   | TINYTEXT, TEXT, MEDIUMTEXT, or LONGTEXT2 | :limit => 1 to 4294967296 (default = 65536) 

Reference:

https://hub.packtpub.com/working-rails-activerecord-migrations-models-scaffolding-and-database-completion/

When should each be used?

As a general rule of thumb, use :string for short text input (username, email, password, titles, etc.) and use :text for longer expected input such as descriptions, comment content, etc.

Answer 2

If you are using postgres use text wherever you can, unless you have a size constraint since there is no performance penalty for text vs varchar

There is no performance difference among these three types, apart from increased storage space when using the blank-padded type, and a few extra CPU cycles to check the length when storing into a length-constrained column. While character(n) has performance advantages in some other database systems, there is no such advantage in PostgreSQL; in fact character(n) is usually the slowest of the three because of its additional storage costs. In most situations text or character varying should be used instead

PostsgreSQL manual