58 lines
2.2 KiB
Markdown
58 lines
2.2 KiB
Markdown
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---
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sidebar_position: 8
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title: Postgres searches
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---
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Searching on Postgres-specific column types.
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## Postgres Array searches
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See [this issue](https://github.com/activerecord-hackery/ransack/issues/321) for details.
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## PostgreSQL JSONB searches
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### Using a fixed key
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See here for searching on a fixed key in a JSONB column: https://github.com/activerecord-hackery/ransack/wiki/Using-Ransackers#3-search-on-a-fixed-key-in-a-jsonb--hstore-column
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### Using the JSONB contains operator
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To fully use the power of the JSONB column you may want to filter on any key though:
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Install the [ActiveRecordExtended](https://github.com/GeorgeKaraszi/ActiveRecordExtended) gem to add the `contains` arel predicate to your project. It let's you use the [Postgres contains operator @>](https://www.postgresql.org/docs/12/functions-json.html#FUNCTIONS-JSONB-OP-TABLE).
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Add a custom predicate in the `config/initializers/ransack.rb` file:
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```ruby
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Ransack.configure do |config|
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config.add_predicate 'jcont', arel_predicate: 'contains', formatter: proc { |v| JSON.parse(v) }
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end
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```
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Now you can ransack the JSONB columns using the _jcont predicate. For example the Person model has a `data` JSONB column, find entries where the column contains the {"group": "experts"} key-value pair:
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Person.ransack(data_jcont: '{"group": "experts"}').result.to_sql
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SELECT "persons".* FROM "persons" WHERE "persons"."data" @> '"{\"group\": \"experts\"}"'
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If you have a GIN index on that column, the database will quickly be able to find that result.
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### Treating the column as a string
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Warning: This method converts the column to a string and matches the given string to the result. This will be slow on large data_sets and does not make good use of the JSONB capabilities of Postgres, such as indexes.
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```ruby
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class Contact < ApplicationRecord
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ransacker :within_json do |parent|
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Arel.sql("table.jsonb_data::text")
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end
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end
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Contact.all.ransack("within_json_cont" => "my")
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```
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Will generate
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`SELECT "contacts".* FROM "contacts" WHERE contacts.json_data ILIKE '%my%'`
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Note that this search treats the entire JSON as string, including parens, etc. i.e. you can search for e.g.: `Contact.all.ransack("within_json_cont" => '{"key": "value"}')`
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