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Diffstat (limited to 'guides/source/active_record_postgresql.md')
| -rw-r--r-- | guides/source/active_record_postgresql.md | 80 |
1 files changed, 56 insertions, 24 deletions
diff --git a/guides/source/active_record_postgresql.md b/guides/source/active_record_postgresql.md index 4d9c1776f4..9d495dfacb 100644 --- a/guides/source/active_record_postgresql.md +++ b/guides/source/active_record_postgresql.md @@ -29,8 +29,8 @@ that are supported by the PostgreSQL adapter. ### Bytea -* [type definition](http://www.postgresql.org/docs/9.3/static/datatype-binary.html) -* [functions and operators](http://www.postgresql.org/docs/9.3/static/functions-binarystring.html) +* [type definition](http://www.postgresql.org/docs/current/static/datatype-binary.html) +* [functions and operators](http://www.postgresql.org/docs/current/static/functions-binarystring.html) ```ruby # db/migrate/20140207133952_create_documents.rb @@ -49,8 +49,8 @@ Document.create payload: data ### Array -* [type definition](http://www.postgresql.org/docs/9.3/static/arrays.html) -* [functions and operators](http://www.postgresql.org/docs/9.3/static/functions-array.html) +* [type definition](http://www.postgresql.org/docs/current/static/arrays.html) +* [functions and operators](http://www.postgresql.org/docs/current/static/functions-array.html) ```ruby # db/migrate/20140207133952_create_books.rb @@ -83,7 +83,7 @@ Book.where("array_length(ratings, 1) >= 3") ### Hstore -* [type definition](http://www.postgresql.org/docs/9.3/static/hstore.html) +* [type definition](http://www.postgresql.org/docs/current/static/hstore.html) NOTE: you need to enable the `hstore` extension to use hstore. @@ -112,8 +112,8 @@ profile.save! ### JSON -* [type definition](http://www.postgresql.org/docs/9.3/static/datatype-json.html) -* [functions and operators](http://www.postgresql.org/docs/9.3/static/functions-json.html) +* [type definition](http://www.postgresql.org/docs/current/static/datatype-json.html) +* [functions and operators](http://www.postgresql.org/docs/current/static/functions-json.html) ```ruby # db/migrate/20131220144913_create_events.rb @@ -138,10 +138,10 @@ Event.where("payload->>'kind' = ?", "user_renamed") ### Range Types -* [type definition](http://www.postgresql.org/docs/9.3/static/rangetypes.html) -* [functions and operators](http://www.postgresql.org/docs/9.3/static/functions-range.html) +* [type definition](http://www.postgresql.org/docs/current/static/rangetypes.html) +* [functions and operators](http://www.postgresql.org/docs/current/static/functions-range.html) -This type is mapped to Ruby [`Range`](http://www.ruby-doc.org/core-2.1.1/Range.html) objects. +This type is mapped to Ruby [`Range`](http://www.ruby-doc.org/core-2.2.2/Range.html) objects. ```ruby # db/migrate/20130923065404_create_events.rb @@ -173,7 +173,7 @@ event.ends_at # => Thu, 13 Feb 2014 ### Composite Types -* [type definition](http://www.postgresql.org/docs/9.3/static/rowtypes.html) +* [type definition](http://www.postgresql.org/docs/current/static/rowtypes.html) Currently there is no special support for composite types. They are mapped to normal text columns: @@ -213,7 +213,7 @@ contact.save! ### Enumerated Types -* [type definition](http://www.postgresql.org/docs/9.3/static/datatype-enum.html) +* [type definition](http://www.postgresql.org/docs/current/static/datatype-enum.html) Currently there is no special support for enumerated types. They are mapped as normal text columns: @@ -242,14 +242,17 @@ article.save! ### UUID -* [type definition](http://www.postgresql.org/docs/9.3/static/datatype-uuid.html) -* [generator functions](http://www.postgresql.org/docs/9.3/static/uuid-ossp.html) +* [type definition](http://www.postgresql.org/docs/current/static/datatype-uuid.html) +* [pgcrypto generator function](http://www.postgresql.org/docs/current/static/pgcrypto.html#AEN159361) +* [uuid-ossp generator functions](http://www.postgresql.org/docs/current/static/uuid-ossp.html) +NOTE: you need to enable the `pgcrypto` (only PostgreSQL >= 9.4) or `uuid-ossp` +extension to use uuid. ```ruby # db/migrate/20131220144913_create_revisions.rb create_table :revisions do |t| - t.column :identifier, :uuid + t.uuid :identifier end # app/models/revision.rb @@ -263,10 +266,35 @@ revision = Revision.first revision.identifier # => "a0eebc99-9c0b-4ef8-bb6d-6bb9bd380a11" ``` +You can use `uuid` type to define references in migrations: + +```ruby +# db/migrate/20150418012400_create_blog.rb +enable_extension 'pgcrypto' unless extension_enabled?('pgcrypto') +create_table :posts, id: :uuid, default: 'gen_random_uuid()' + +create_table :comments, id: :uuid, default: 'gen_random_uuid()' do |t| + # t.belongs_to :post, type: :uuid + t.references :post, type: :uuid +end + +# app/models/post.rb +class Post < ActiveRecord::Base + has_many :comments +end + +# app/models/comment.rb +class Comment < ActiveRecord::Base + belongs_to :post +end +``` + +See [this section](#uuid-primary-keys) for more details on using UUIDs as primary key. + ### Bit String Types -* [type definition](http://www.postgresql.org/docs/9.3/static/datatype-bit.html) -* [functions and operators](http://www.postgresql.org/docs/9.3/static/functions-bitstring.html) +* [type definition](http://www.postgresql.org/docs/current/static/datatype-bit.html) +* [functions and operators](http://www.postgresql.org/docs/current/static/functions-bitstring.html) ```ruby # db/migrate/20131220144913_create_users.rb @@ -289,10 +317,10 @@ user.save! ### Network Address Types -* [type definition](http://www.postgresql.org/docs/9.3/static/datatype-net-types.html) +* [type definition](http://www.postgresql.org/docs/current/static/datatype-net-types.html) The types `inet` and `cidr` are mapped to Ruby -[`IPAddr`](http://www.ruby-doc.org/stdlib-2.1.1/libdoc/ipaddr/rdoc/IPAddr.html) +[`IPAddr`](http://www.ruby-doc.org/stdlib-2.2.2/libdoc/ipaddr/rdoc/IPAddr.html) objects. The `macaddr` type is mapped to normal text. ```ruby @@ -324,7 +352,7 @@ macbook.address ### Geometric Types -* [type definition](http://www.postgresql.org/docs/9.3/static/datatype-geometric.html) +* [type definition](http://www.postgresql.org/docs/current/static/datatype-geometric.html) All geometric types, with the exception of `points` are mapped to normal text. A point is casted to an array containing `x` and `y` coordinates. @@ -333,12 +361,13 @@ A point is casted to an array containing `x` and `y` coordinates. UUID Primary Keys ----------------- -NOTE: you need to enable the `uuid-ossp` extension to generate UUIDs. +NOTE: you need to enable the `pgcrypto` (only PostgreSQL >= 9.4) or `uuid-ossp` +extension to generate random UUIDs. ```ruby # db/migrate/20131220144913_create_devices.rb -enable_extension 'uuid-ossp' unless extension_enabled?('uuid-ossp') -create_table :devices, id: :uuid, default: 'uuid_generate_v4()' do |t| +enable_extension 'pgcrypto' unless extension_enabled?('pgcrypto') +create_table :devices, id: :uuid, default: 'gen_random_uuid()' do |t| t.string :kind end @@ -351,6 +380,9 @@ device = Device.create device.id # => "814865cd-5a1d-4771-9306-4268f188fe9e" ``` +NOTE: `uuid_generate_v4()` (from `uuid-ossp`) is assumed if no `:default` option was +passed to `create_table`. + Full Text Search ---------------- @@ -378,7 +410,7 @@ Document.where("to_tsvector('english', title || ' ' || body) @@ to_tsquery(?)", Database Views -------------- -* [view creation](http://www.postgresql.org/docs/9.3/static/sql-createview.html) +* [view creation](http://www.postgresql.org/docs/current/static/sql-createview.html) Imagine you need to work with a legacy database containing the following table: |