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Rails ActiveRecord Data Types

Amirul Asyraf
Musician & ProgrammΞr 🤘
・2 min read

I usually curios to know about Data Types for ActiveRecord, but the Active Record Migration documentation itself does not have that information.

So, I do some Google search and here is the TL;DR.

The ActiveRecord data types available in Rails 6;

  • :primary_key
  • :string: short text
  • :text: long text
  • :integer: whole numbers [-4, 0, 9, 772]
  • :float: double-precision floating-point numbers [3244.90]
  • :decimal: high-precision floating-point numbers [3244.2342343789212]
  • :datetime
  • :time
  • :date
  • :binary: 1 / 0
  • :boolean: true or false

These data types are used in instances such as migrations.

def change
  create_table :categories do |t|
    t.string :title
    t.boolean :is_subcategory
    t.string :permalink
    t.timestamps
  end
end
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Specific DBMS Data Type

MySQL Data Types

NATIVE_DATABASE_TYPES = {
        primary_key: "bigint auto_increment PRIMARY KEY",
        string:      { name: "varchar", limit: 255 },
        text:        { name: "text" },
        integer:     { name: "int", limit: 4 },
        float:       { name: "float", limit: 24 },
        decimal:     { name: "decimal" },
        datetime:    { name: "datetime" },
        timestamp:   { name: "timestamp" },
        time:        { name: "time" },
        date:        { name: "date" },
        binary:      { name: "blob" },
        blob:        { name: "blob" },
        boolean:     { name: "tinyint", limit: 1 },
        json:        { name: "json" },
      }
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PostgreSQL Data Types

NATIVE_DATABASE_TYPES = {
        primary_key: "bigserial primary key",
        string:      { name: "character varying" },
        text:        { name: "text" },
        integer:     { name: "integer", limit: 4 },
        float:       { name: "float" },
        decimal:     { name: "decimal" },
        datetime:    {}, # set dynamically based on datetime_type
        timestamp:   { name: "timestamp" },
        timestamptz: { name: "timestamptz" },
        time:        { name: "time" },
        date:        { name: "date" },
        daterange:   { name: "daterange" },
        numrange:    { name: "numrange" },
        tsrange:     { name: "tsrange" },
        tstzrange:   { name: "tstzrange" },
        int4range:   { name: "int4range" },
        int8range:   { name: "int8range" },
        binary:      { name: "bytea" },
        boolean:     { name: "boolean" },
        xml:         { name: "xml" },
        tsvector:    { name: "tsvector" },
        hstore:      { name: "hstore" },
        inet:        { name: "inet" },
        cidr:        { name: "cidr" },
        macaddr:     { name: "macaddr" },
        uuid:        { name: "uuid" },
        json:        { name: "json" },
        jsonb:       { name: "jsonb" },
        ltree:       { name: "ltree" },
        citext:      { name: "citext" },
        point:       { name: "point" },
        line:        { name: "line" },
        lseg:        { name: "lseg" },
        box:         { name: "box" },
        path:        { name: "path" },
        polygon:     { name: "polygon" },
        circle:      { name: "circle" },
        bit:         { name: "bit" },
        bit_varying: { name: "bit varying" },
        money:       { name: "money" },
        interval:    { name: "interval" },
        oid:         { name: "oid" },
      }
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Rails data types mapping to different DB data types:

It is important to know not only the types but the mapping of these types to the database types, too:

Data type mapping 1
Data type mapping 2


The easy way ✌️

You can access this list everytime you want (even if you don't have Internet access) through:

rails generate model -h
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The end


resources;

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