Module: ConnectionManager::ConnectionHelpers

Included in:
ActiveRecord::Base
Defined in:
lib/connection_manager/helpers/connection_helpers.rb

Constant Summary collapse

@@managed_connections = 
HashWithIndifferentAccess.new

Instance Method Summary collapse

Instance Method Details

#add_managed_connections(yml_key, value) ⇒ Object 



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# File 'lib/connection_manager/helpers/connection_helpers.rb', line 43

def add_managed_connections(yml_key,value)
  @@managed_connections[yml_key] ||= []
  @@managed_connections[yml_key] << value unless @@managed_connections[yml_key].include?(value)
  @@managed_connections
end

#current_database_name ⇒ Object Also known as: database_name, current_schema_name, schema_name

Returns the database_name of the connection unless set otherwise



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# File 'lib/connection_manager/helpers/connection_helpers.rb', line 7

def current_database_name
  return "#{connection.config[:database].to_s}" if @current_database_name.blank?
  @current_database_name
end

#current_database_name=(current_database_name) ⇒ Object Also known as: database_name=, current_schema_name=, schema_name=

Sometimes we need to manually set the database name, like when the connection has a database but our table is in a different database/schema but on the same DMS.



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# File 'lib/connection_manager/helpers/connection_helpers.rb', line 19

def current_database_name=current_database_name
  @current_database_name= current_database_name
end

#establish_managed_connection(yml_key, opts = {}) ⇒ Object

Establishes and checks in a connection, normally for abstract classes AKA connection classes.

Options:

  • :abstract_class - used the set #abstract_class, default is true

  • :readonly - force all instances to readonly

  • :class_name - name of connection class name, default is current class name

  • :table_name_prefix - prefix to append to table name for cross database joins,

    default is the "#{self.database_name}."

EX:

class MyConnection < ActiveRecord::Base
  establish_managed_connection :key_from_db_yml,{:readonly => true}
end



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# File 'lib/connection_manager/helpers/connection_helpers.rb', line 99

def establish_managed_connection(yml_key,opts={})
  @yml_key = yml_key
  opts = {:class_name => self.name, 
    :abstract_class => true}.merge(opts)   
  establish_connection(yml_key)     
  self.abstract_class = opts[:abstract_class]
  set_to_readonly if (readonly? || opts[:readonly] || self.connection.readonly?)
  add_managed_connections(yml_key,opts[:class_name])
  use_database(self.current_database_name,opts)
end

#managed_connection_classes ⇒ Object 



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# File 'lib/connection_manager/helpers/connection_helpers.rb', line 49

def managed_connection_classes
  managed_connections.values.flatten
end

#managed_connections ⇒ Object

A place to store managed connections



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# File 'lib/connection_manager/helpers/connection_helpers.rb', line 39

def managed_connections
  @@managed_connections
end

#readonly=(readonly) ⇒ Object

Allow setting of readonly at the model level



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# File 'lib/connection_manager/helpers/connection_helpers.rb', line 34

def readonly=readonly
  @readonly = readonly
end

#readonly? ⇒ Boolean

Returns true if this is a readonly only a readonly model If the connection.readonly? then the model that uses the connection must be readonly.

Returns:

  • (Boolean) 


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# File 'lib/connection_manager/helpers/connection_helpers.rb', line 29

def readonly?
  ((@readonly == true)||connection.readonly?)
end

#set_to_readonly ⇒ Object

Override ActiveRecord::Base instance method readonly? to force readonly connections.



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# File 'lib/connection_manager/helpers/connection_helpers.rb', line 112

def set_to_readonly
  self.readonly = true
  define_method(:readonly?) do 
    true
  end  
end

#use_database(database_name = nil, opts = {}) ⇒ Object Also known as: use_schema

Tell Active Record to use a different database/schema on this model. You may call #use_database when your schemas reside on the same database server and you do not want to create extra connection class and database.yml entries.

Options:

  • :table_name_prefix - the prefix required for making cross database/schema

joins for you database management system. By default table_name_prefix is the database/schema name followed by a period EX: “my_database.”

  • :table_name - the table name for the model if it does not match ActiveRecord

naming conventions

EX: class LegacyUser < ActiveRecord::Base

  use_database('DBUser', :table_name => 'UserData')
end

LegacyUser.limit(1).to_sql => "SELECT * FROM `BDUser`.`UserData` LIMIT 1



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# File 'lib/connection_manager/helpers/connection_helpers.rb', line 74

def use_database(database_name=nil,opts={})
  self.current_database_name = database_name if database_name
  opts[:table_name_prefix] = "#{self.current_database_name}." if opts[:table_name_prefix].blank? && self.connection.cross_database_support?
  unless self.abstract_class? || self.name == "ActiveRecord::Base"
    opts[:table_name] = self.table_name if opts[:table_name].blank?
    opts[:table_name].gsub!(self.table_name_prefix,'') unless self.table_name_prefix.blank?
    self.table_name = "#{opts[:table_name_prefix]}#{opts[:table_name]}"
  end
  self.table_name_prefix = opts[:table_name_prefix] unless opts[:table_name_prefix].blank?
end

#yml_key ⇒ Object 



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# File 'lib/connection_manager/helpers/connection_helpers.rb', line 53

def yml_key
  @yml_key
end