From fcd0ac066e0959a9f4fa4459a27e041abe8eb52a Mon Sep 17 00:00:00 2001 From: Yves Senn Date: Tue, 10 Jun 2014 10:21:15 +0200 Subject: docs, refactor docs about column modifiers. [ci skip] [Matthew Draper & Yves Senn] This is a follow up to #15602 which rendered the guides in a weird state: > You can also specify some options just after the field type between curly braces. You can use the following modifiers: > `null` Allows or disallows `NULL` values in the column. > NOTE: `null` and `default` cannot be specified via command line. The modifiers are now moved into a separate section. The generator simply referes to that section. Related to #15583. /cc @JuanitoFatas --- guides/source/active_record_migrations.md | 32 +++++++++++++++++++------------ 1 file changed, 20 insertions(+), 12 deletions(-) (limited to 'guides/source/active_record_migrations.md') diff --git a/guides/source/active_record_migrations.md b/guides/source/active_record_migrations.md index ef95a28564..5a550d9e55 100644 --- a/guides/source/active_record_migrations.md +++ b/guides/source/active_record_migrations.md @@ -293,19 +293,10 @@ end You can append as many column name/type pairs as you want. -### Supported Type Modifiers +### Passing Modifiers -You can also specify some options just after the field type between curly -braces. You can use the following modifiers: - -* `limit` Sets the maximum size of the `string/text/binary/integer` fields. -* `precision` Defines the precision for the `decimal` fields, representing the total number of digits in the number. -* `scale` Defines the scale for the `decimal` fields, representing the number of digits after the decimal point. -* `polymorphic` Adds a `type` column for `belongs_to` associations. -* `null` Allows or disallows `NULL` values in the column. -* `default` Allows to set a default value on the column. NOTE: If using a dynamic value (such as date), the default will only be calculated the first time (e.g. on the date the migration is applied.) - -NOTE: `null` and `default` cannot be specified via command line. +Some commonly used [type modifiers](#column-modifiers) can be passed directly on +the command line. They are enclosed by curly braces and follow the field type: For instance, running: @@ -324,6 +315,8 @@ class AddDetailsToProducts < ActiveRecord::Migration end ``` +TIP: Have a look at the generators help output for further details. + Writing a Migration ------------------- @@ -441,6 +434,21 @@ change_column_default :products, :approved, false This sets `:name` field on products to a `NOT NULL` column and the default value of the `:approved` field to false. +### Column Modifiers + +Column modifiers can be applied when creating or changing a column: + +* `limit` Sets the maximum size of the `string/text/binary/integer` fields. +* `precision` Defines the precision for the `decimal` fields, representing the total number of digits in the number. +* `scale` Defines the scale for the `decimal` fields, representing the number of digits after the decimal point. +* `polymorphic` Adds a `type` column for `belongs_to` associations. +* `null` Allows or disallows `NULL` values in the column. +* `default` Allows to set a default value on the column. NOTE: If using a dynamic value (such as date), the default will only be calculated the first time (e.g. on the date the migration is applied.) +* `index` Adds an index for the column. + +Some adapters may support additional options; see the adapter specific API docs +for further information. + ### When Helpers aren't Enough If the helpers provided by Active Record aren't enough you can use the `execute` -- cgit v1.2.3