|
Migration column type… |
Converts to MySQL field type… |
Available options |
|
:binary |
TINYBLOB, BLOB, MEDIUMBLOB, or LONGBLOB2 |
:limit => 1 to 4294967296 (default = 65536)2 |
|
:boolean |
TINYINT(1) |
- |
|
:date |
DATE |
- |
|
:datetime |
DATETIME |
- |
|
:decimal |
DECIMAL |
:precision => 1 to 63 (default = 10) :scale => 0 to 30 (default = 0)3 |
|
:float |
FLOAT |
- |
|
:integer |
INT |
:limit => 1 to 11 (default = 11) |
|
:primary_key |
INT(11) AUTO_INCREMENT PRIMARY KEY |
- |
|
:string |
VARCHAR |
:limit => 1 to 255 (default = 255) |
|
:text |
TINYTEXT, TEXT, MEDIUMTEXT, or LONGTEXT2 |
:limit => 1 to 4294967296 (default = 65536)2 |
|
:time |
TIME |
- |
|
:timestamp |
DATETIME |
- |
All column types accept a :null or :default option:
- :null
The default value for this is true (i.e. the field’s value can be null in thedatabase). Set :null => false if you don’t want to allow nulls in thedatabase field, e.g.- t.column :first_name, :string, :null => false
Note that if you allow nulls in a field (:null => true or not specified), youdon’t need to specify :default => NULL: NULL is already the default for a field, which allows null values.
- :default
Specify the default value for the database field when new records are addedto the table. The value you specify should be of the correct data type for the column, e.g.- t.column :completed, :default => true (for a :boolean column)
- t.column :size, :default => 1 (for an :integer column)
- t.column :name, :default => ‘Unknown’ (for a :string column)
- t.column :reminder_on, :default => Time.now (for a :datetime, :date, :time or :timestamp column)
The :limit option on a :blob or :text column specifies the size of the database field in bytes. You can set this directly in bytes, or use a convenience method to specify the size, e.g. 2.kilobytes, 2.megabytes, 2.gigabytes(!). Note that MySQL will actually create a field with a data type, which encompasses the size you specify, i.e.
- 1 to 256 bytes: TINYBLOB or TINYTEXT
- 257 to 65536 bytes (64KiB): BLOB or TEXT
- 65537 to 16777216 bytes (16 MiB): MEDIUMBLOB or MEDIUMTEXT
- 16777217 to 4294967296 bytes (4 GiB): LONGBLOB or LONGTEXT
