instance method `establish_connection`

Ruby on Rails 5.2.8.1

Since v4.0.13

Available in: v4.0.13 v4.1.16 v4.2.9 v5.2.8.1 v6.0.6 v6.1.7.10 v7.0.10 v7.1.6 v7.2.3 v8.0.4 v8.1.2

Compare with:

establish_connection(config = nil)

Establishes the connection to the database. Accepts a hash as input where the :adapter key must be specified with the name of a database adapter (in lower-case) example for regular databases (MySQL, PostgreSQL, etc):

ActiveRecord::Base.establish_connection(
  adapter:  "mysql2",
  host:     "localhost",
  username: "myuser",
  password: "mypass",
  database: "somedatabase"
)

Example for SQLite database:

ActiveRecord::Base.establish_connection(
  adapter:  "sqlite3",
  database: "path/to/dbfile"
)

Also accepts keys as strings (for parsing from YAML for example):

ActiveRecord::Base.establish_connection(
  "adapter"  => "sqlite3",
  "database" => "path/to/dbfile"
)

Or a URL:

ActiveRecord::Base.establish_connection(
  "postgres://myuser:mypass@localhost/somedatabase"
)

In case ActiveRecord::Base.configurations is set (Rails automatically loads the contents of config/database.yml into it), a symbol can also be given as argument, representing a key in the configuration hash:

ActiveRecord::Base.establish_connection(:production)

The exceptions AdapterNotSpecified, AdapterNotFound and ArgumentError may be returned on an error.

Parameters

config opt = nil

Source

# File activerecord/lib/active_record/connection_handling.rb, line 49
    def establish_connection(config = nil)
      raise "Anonymous class is not allowed." unless name

      config ||= DEFAULT_ENV.call.to_sym
      spec_name = self == Base ? "primary" : name
      self.connection_specification_name = spec_name

      resolver = ConnectionAdapters::ConnectionSpecification::Resolver.new(Base.configurations)
      spec = resolver.resolve(config).symbolize_keys
      spec[:name] = spec_name

      connection_handler.establish_connection(spec)
    end

Defined in activerecord/lib/active_record/connection_handling.rb line 49 · View on GitHub · Improve this page · Find usages on GitHub

Defined in ActiveRecord::ConnectionHandling

Signature

Parameters