Module: UsesStoredProcedures::ClassMethods

Defined in:
lib/uses_stored_procedures.rb

Instance Method Summary collapse

Instance Method Details

#call_stored_proc_verb ⇒ Object

Return the SQL verb for calling a stored procedure.



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# File 'lib/uses_stored_procedures.rb', line 44

def call_stored_proc_verb()
  case ActiveRecord::Base.connection.adapter_name.to_sym
  when :Mysql2, :MySQL
    'call'
  when :PostgreSQL
    'select'
  when :SQLServer
    'exec'
  else
    raise "uses_stored_procedurs does not support your connection adapter"
  end        
end

#exec_stored_proc(name, call_stored_proc_verb, filter, args) ⇒ Object

Run the stored procedure with the arguments provided and send them through a filter method or block if specified.



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# File 'lib/uses_stored_procedures.rb', line 74

def exec_stored_proc(name, call_stored_proc_verb, filter, args) #:nodoc:
  sql = "#{call_stored_proc_verb} #{name} (" + args.map {|a| "'#{a}'"}.join(',') + ")"

  # Call the stored procedure. Note the need to reset the connection
  # because the mysql connection tends to hangup when stored procedures
  # are called. Note that testing for ::connected? doesn't work.
  #
  # TODO: investigate why stored procedures cause connection hangups.
  records = ActiveRecord::Base.connection.select_all(sql)
  ActiveRecord::Base.connection.reconnect!

  filter_stored_proc_results(records, filter)
end

#install_stored_proc_methods(name, proc_name, call_stored_proc_verb, filter) ⇒ Object

Define the class and instance methods. Note the need to create a singleton class instance to create the stored procedure class method.



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# File 'lib/uses_stored_procedures.rb', line 60

def install_stored_proc_methods(name, proc_name, call_stored_proc_verb, filter) #:nodoc:
  define_method name do |*args| 
    self.class.exec_stored_proc(proc_name, call_stored_proc_verb, filter, args) 
  end

  singleton_class = class << self; self; end
  singleton_class.send(:define_method, name) do |*args| 
    exec_stored_proc(proc_name, call_stored_proc_verb, filter, args) 
  end

end

#uses_stored_proc(name, *args, &block) ⇒ Object

Add a stored procedure that can ba called on a class or a class instance.

By default, it is assumed that the stored procedure has the same name as a string.

include:

* :proc_name - is the name of the stored procedure. Use this if the
name doesn't match the name paramter
* :filter - is a class method used to filter the return results. The
method should take a HashWithAttributes instance and return an object
for the array entry

and returns an object for the array entry.

Parameters:

  • name (Symbol) —

    is the symbolic name of the method to be created.

  • args —

    is a variable list of optional arguments. Available Options

  • block (Proc) —

    • is a block that takes a HashWithAttributes instance



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# File 'lib/uses_stored_procedures.rb', line 34

def uses_stored_proc(name, *args, &block)
  options   = args.extract_options!
  proc_name = options[:proc_name] || name.to_s
  
  # Install the row mapper block or method
  self.install_stored_proc_methods(name, proc_name, call_stored_proc_verb, options[:filter] || block)
end