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-rw-r--r--guides/source/active_record_postgresql.md91
1 files changed, 88 insertions, 3 deletions
diff --git a/guides/source/active_record_postgresql.md b/guides/source/active_record_postgresql.md
index ae767769dd..14f7f4dccd 100644
--- a/guides/source/active_record_postgresql.md
+++ b/guides/source/active_record_postgresql.md
@@ -12,10 +12,9 @@ It describes how to properly setup Active Record for PostgreSQL.
After reading this guide, you will know:
-
* How to use PostgreSQL's datatypes.
-* How to use UUID Primary keys.
-* How to implement Full text search with PostgreSQL.
+* How to use UUID primary keys.
+* How to implement full text search with PostgreSQL.
--------------------------------------------------------------------------------
@@ -291,6 +290,33 @@ user.save!
The types `inet` and `cidr` are mapped to Ruby [`IPAddr`](http://www.ruby-doc.org/stdlib-2.1.1/libdoc/ipaddr/rdoc/IPAddr.html) objects. The
`macaddr` type is mapped to normal text.
+```ruby
+# db/migrate/20140508144913_create_devices.rb
+create_table(:devices, force: true) do |t|
+ t.inet 'ip'
+ t.cidr 'network'
+ t.macaddr 'address'
+end
+
+# app/models/device.rb
+class Device < ActiveRecord::Base
+end
+
+# Usage
+macbook = Device.create(ip: "192.168.1.12",
+ network: "192.168.2.0/24",
+ address: "32:01:16:6d:05:ef")
+
+macbook.ip
+# => #<IPAddr: IPv4:192.168.1.12/255.255.255.255>
+
+macbook.network
+# => #<IPAddr: IPv4:192.168.2.0/255.255.255.0>
+
+macbook.address
+# => "32:01:16:6d:05:ef"
+```
+
### Geometric Types
* [type definition](http://www.postgresql.org/docs/9.3/static/datatype-geometric.html)
@@ -345,3 +371,62 @@ Document.where("to_tsvector('english', title || ' ' || body) @@ to_tsquery(?)",
Views
-----
+
+* [view creation](http://www.postgresql.org/docs/9.3/static/sql-createview.html)
+
+Imagine you need to work with a legacy database containing the following table:
+
+```
+rails_pg_guide=# \d "TBL_ART"
+ Table "public.TBL_ART"
+ Column | Type | Modifiers
+------------+-----------------------------+------------------------------------------------------------
+ INT_ID | integer | not null default nextval('"TBL_ART_INT_ID_seq"'::regclass)
+ STR_TITLE | character varying |
+ STR_STAT | character varying | default 'draft'::character varying
+ DT_PUBL_AT | timestamp without time zone |
+ BL_ARCH | boolean | default false
+Indexes:
+ "TBL_ART_pkey" PRIMARY KEY, btree ("INT_ID")
+```
+
+This table does not follow the Rails conventions at all.
+Because simple PostgreSQL views are updateable by default,
+we can wrap it as follows:
+
+```ruby
+# db/migrate/20131220144913_create_articles_view.rb
+execute <<-SQL
+CREATE VIEW articles AS
+ SELECT "INT_ID" AS id,
+ "STR_TITLE" AS title,
+ "STR_STAT" AS status,
+ "DT_PUBL_AT" AS published_at,
+ "BL_ARCH" AS archived
+ FROM "TBL_ART"
+ WHERE "BL_ARCH" = 'f'
+ SQL
+
+# app/models/article.rb
+class Article < ActiveRecord::Base
+ self.primary_key = "id"
+ def archive!
+ update_attribute :archived, true
+ end
+end
+
+# Usage
+first = Article.create! title: "Winter is coming",
+ status: "published",
+ published_at: 1.year.ago
+second = Article.create! title: "Brace yourself",
+ status: "draft",
+ published_at: 1.month.ago
+
+Article.count # => 1
+first.archive!
+p Article.count # => 2
+```
+
+Note: This application only cares about non-archived `Articles`. A view also
+allows for conditions so we can exclude the archived `Articles` directly.