Module: Highland::DatabaseMethods

Included in:
Highland
Defined in:
lib/highland/database_methods.rb

Overview

DatabaseMethods are not the part of the user API. These methods are the fundamentals of the one. They work with static hashes and manage virtual ones. It’s not recommended to work with these methods directly.

Instance Method Summary collapse

Instance Method Details

#clear_static ⇒ Object

Clears static hash (collection).



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# File 'lib/highland/database_methods.rb', line 129

def clear_static
  File.truncate(@file, 0)
end

#clear_virtual ⇒ Object

Clears virtual hash and virtual helper.



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# File 'lib/highland/database_methods.rb', line 115

def clear_virtual
  @vhash, @vhelper = {}, {}
end

#delete(*query) ⇒ Object

Deletes element from collection.



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# File 'lib/highland/database_methods.rb', line 135

def delete(*query)
  find_db(*query).each_key do |id|
    @vhash.remove!(id)
  end
  load_vhelper
  clear_static
  insert_shash(@vhash)
  return true
end

#find_db(*query) ⇒ Object

Finds hash elements according to the query.



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# File 'lib/highland/database_methods.rb', line 79

def find_db(*query)
  if query[0].class == Fixnum
    id = query[0]
    output = {}
    output[id] = @vhash[id] if @vhash[id] != nil
    return output
  end
  if query[0].class == Hash
  	q = query[0]
    ids = []
    q.each_key do |column|
      ids << @vhelper[column.to_s][q[column]]
    end
    res = ids.inject(ids.first){ |sim,cur| sim & cur }
    return {} if res.class != Array or res == []
    output = {}
    res.each do |id|
      next if @vhash[id] == nil
      output[id] = @vhash[id]
    end
    return output
  end
end

#generate_hl ⇒ Object

Creates static hash in the database folder.



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# File 'lib/highland/database_methods.rb', line 22

def generate_hl
  File.new(@file, "w")
end

#init_file(shash) ⇒ Object

Defines @file instance variable.



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# File 'lib/highland/database_methods.rb', line 15

def init_file(shash)
  @file = shash
   generate_hl if File.exists?(@file) == false
end

#insert_shash(element) ⇒ Object

Inserts hash element into the static hash.



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# File 'lib/highland/database_methods.rb', line 105

def insert_shash(element)
  File.open(@file, 'a') do |file|
    element.each_key do |id|
      file.puts "#{id} => #{element[id]},"
    end        
  end
end

#insert_vhash(element) ⇒ Object

Inserts hash element into the virtual hash.



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# File 'lib/highland/database_methods.rb', line 57

def insert_vhash(element)
  element.each_key do |key|
    @vhash[key] = element[key]
  end
end

#insert_vhelper(element) ⇒ Object

Inserts hash element into the virtual helper.



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# File 'lib/highland/database_methods.rb', line 65

def insert_vhelper(element)
  element.each_key do |id|
    element[id].each_key do |column|
      @vhelper[column] ||= {}
      item = element[id][column]["value"]
      @vhelper[column][item] ||= []
      @vhelper[column][item] << id
    end
  end
  update_columns
end

#load_vhash(shash) ⇒ Object

Loads virtual hash.



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# File 'lib/highland/database_methods.rb', line 28

def load_vhash(shash)
  init_file(shash)
  data = "{#{rio(@file).contents}}"
  @vhash = eval(data)
end

#load_vhelper ⇒ Object

Loads virtual helper.



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# File 'lib/highland/database_methods.rb', line 42

def load_vhelper
  @vhelper = {}
  @vhash.each_key do |id|
    @vhash[id].each_key do |column|
      @vhelper[column] ||= {}
      item = @vhash[id][column]["value"]
      @vhelper[column][item] ||= []
      @vhelper[column][item] << id
    end
  end
  update_columns
end

#reload_virtual ⇒ Object

Reloads virtual hash and virtual helper.



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# File 'lib/highland/database_methods.rb', line 121

def reload_virtual
  clear_virtual
  load_vhash(@file)
  load_vhelper
end

#return_vhash ⇒ Object

Returns virtual hash.



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# File 'lib/highland/database_methods.rb', line 161

def return_vhash
  @vhash
end

#return_vhelper ⇒ Object

Returns virtual helper.



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# File 'lib/highland/database_methods.rb', line 167

def return_vhelper
  @vhelper
end

#update_columns ⇒ Object

Assigns the latest information about columns the @columns.



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# File 'lib/highland/database_methods.rb', line 36

def update_columns
  @columns = @vhelper.keys
end

#update_db(*query) ⇒ Object

Updates element.



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# File 'lib/highland/database_methods.rb', line 147

def update_db(*query)
  id = query[0][:id]
  query[0].each_key do |key|
    next if key == :id
    @vhash[id][key.to_s]["value"] = query[0][key] if @vhash[id].has_key?(key.to_s)
  end
  load_vhelper
  clear_static
  insert_shash(@vhash)
  return true      
end