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

User · Answer

String translates to  Varchar  in your database  while text translates to  text   A varchar can contain far less items  a text can be of  almost  any length   For an in-depth analysis with good references check http   www pythian com news 7129 text-vs-varchar   Edit  Some database engines can load varchar in one go  but store text  and blob  outside of the table  A SELECT name  amount FROM products could  be a lot slower when using text for name than when you use varchar  And since Rails  by default loads records with SELECT   FROM    your text-columns will be loaded  This will probably never be a real problem in your or my app  though  Premature optimization is       But knowing that text is not always  free  is good to know

User · Answer

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

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If you are using oracle    STRING will be created as VARCHAR 255  column and TEXT  as a CLOB   NATIVE DATABASE TYPES         primary key   NUMBER 38  NOT NULL PRIMARY KEY       string    name   VARCHAR2   limit  255        text    name   CLOB         ntext    name   NCLOB         integer    name   NUMBER   limit  38        float    name   BINARY FLOAT         decimal    name   DECIMAL         datetime    name   TIMESTAMP         timestamp    name   TIMESTAMP         timestamptz    name   TIMESTAMP WITH TIME ZONE         timestampltz    name   TIMESTAMP WITH LOCAL TIME ZONE         time    name   TIMESTAMP         date    name   DATE         binary    name   BLOB         boolean    name   NUMBER   limit  1        raw    name   RAW   limit  2000        bigint    name   NUMBER   limit  19       https   github com rsim oracle-enhanced blob master lib active record connection adapters oracle enhanced adapter rb

User · Answer

Use string for shorter field  like names  address  phone  company  Use Text for larger content  comments  content  paragraphs   My general rule  if it s something that is more than one line  I typically go for text  if it s a short 2-6 words  I go for string   The official rule is 255 for a string   So  if your string is more than 255 characters  go for text

User · Answer

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   gt  1 to 255  default   255     text     TINYTEXT  TEXT  MEDIUMTEXT  or LONGTEXT2    limit   gt  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

User · Answer

The accepted answer is awesome  it properly explains the difference between string vs text  mostly the limit size in the database  but there are a few other gotchas   but I wanted to point out a small issue that got me through it as that answer didn t completely do it for me   The max size  limit    1 to 4294967296 didn t work exactly as put  I needed to go -1 from that max size   I m storing large JSON blobs and they might be crazy huge sometimes   Here s my migration with the larger value in place with the value MySQL doesn t complain about   Note the 5 at the end of the limit instead of 6  class ChangeUserSyncRecordDetailsToText  lt  ActiveRecord  Migration 5 1    def up     change column  user sync records   details   text   limit   gt  4294967295   end    def down     change column  user sync records   details   string   limit   gt  1000   end end

User · Answer

As explained above not just the db datatype it will also affect the view that will be generated if you are scaffolding   string will generate a text field text will generate a text area

User · Answer

If the attribute is matching f text field in form use string  if it is matching f text area use text

User · Answer

String if the size is fixed and small and text if it is variable and big  This is kind of important because text is way bigger than strings  It contains a lot more kilobytes    So for small fields always use string varchar   Fields like  first name  login  email  subject  of a article or post  and example of texts  content body of a post or article  fields for paragraphs etc  String size 1 to 255  default   255    Text size 1 to 4294967296  default   65536 2

[ruby-on-rails] Difference between string and text in rails?

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