Class: DataMiner::Schema

Inherits:
Object
  • Object
show all
Includes:
Blockenspiel::DSL
Defined in:
lib/data_miner/schema.rb

Constant Summary collapse

MAX_INDEX_NAME_LENGTH = 
50
INDEX_PROPERTIES = 
%w{ name columns }
EXTRA_COLUMNS = 
{
  :updated_at => :datetime,
  :created_at => :datetime
}

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(base, position_in_run, create_table_options) ⇒ Schema

Returns a new instance of Schema.



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# File 'lib/data_miner/schema.rb', line 10

def initialize(base, position_in_run, create_table_options)
  @base = base
  @position_in_run = position_in_run
  @create_table_options = create_table_options
  @create_table_options.symbolize_keys!
  DataMiner.log_or_raise ":id => true is not allowed in create_table_options." if @create_table_options[:id] === true
  DataMiner.log_or_raise ":primary_key is not allowed in create_table_options. Use set_primary_key instead." if @create_table_options.has_key?(:primary_key)
  @create_table_options[:id] = false # always
end

Instance Attribute Details

#base ⇒ Object (readonly)

Returns the value of attribute base.



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# File 'lib/data_miner/schema.rb', line 5

def base
  @base
end

#create_table_options ⇒ Object (readonly)

Returns the value of attribute create_table_options.



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# File 'lib/data_miner/schema.rb', line 7

def create_table_options
  @create_table_options
end

#position_in_run ⇒ Object (readonly)

Returns the value of attribute position_in_run.



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# File 'lib/data_miner/schema.rb', line 6

def position_in_run
  @position_in_run
end

Instance Method Details

#_add_columns ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 225

def _add_columns
  ideal_table.columns.each do |ideal|
    place_column ideal.name if column_needs_to_be_placed? ideal.name
  end
end

#_add_extra_columns ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 174

def _add_extra_columns
  EXTRA_COLUMNS.each do |extra_name, extra_type|
    send extra_type, extra_name unless ideal_column extra_name
  end
end

#_add_indexes ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 237

def _add_indexes
  ideal_indexes.each do |ideal|
    next if ideal.name == ideal_primary_key_name # this should already have been taken care of
    place_index ideal.name if index_needs_to_be_placed? ideal.name
  end
end

#_create_table ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 180

def _create_table
  if not resource.table_exists?
    DataMiner.log_debug "CREATING TABLE #{table_name} with #{create_table_options.inspect}"
    connection.create_table table_name, create_table_options do |t|
      t.integer :data_miner_placeholder
    end
    resource.reset_column_information
  end
end

#_remove_columns ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 219

def _remove_columns
  resource.columns_hash.values.each do |actual|
    remove_column actual.name if column_needs_to_be_removed? actual.name
  end
end

#_remove_indexes ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 231

def _remove_indexes
  actual_indexes.each do |actual|
    remove_index actual.name if index_needs_to_be_removed? actual.name
  end
end

#_set_primary_key ⇒ Object

FIXME mysql only



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# File 'lib/data_miner/schema.rb', line 191

def _set_primary_key
  if ideal_primary_key_name == 'id' and not ideal_column('id')
    DataMiner.log_debug "no special primary key set on #{table_name}, so using 'id'"
    column 'id', :primary_key
  end
  actual = actual_column actual_primary_key_name
  ideal = ideal_column ideal_primary_key_name
  if not column_equivalent? actual, ideal
    DataMiner.log_debug "looks like #{table_name} has a bad (or missing) primary key"
    if actual
      DataMiner.log_debug "looks like primary key needs to change from #{actual_primary_key_name} to #{ideal_primary_key_name}, re-creating #{table_name} from scratch"
      connection.drop_table table_name
      resource.reset_column_information
      _create_table
    end
    place_column ideal_primary_key_name
    unless ideal.type.to_s == 'primary_key'
      DataMiner.log_debug "SETTING #{ideal_primary_key_name} AS PRIMARY KEY"
      if ActiveRecord::Base.connection.adapter_name.downcase == 'sqlite'
        connection.execute "CREATE UNIQUE INDEX IDX_#{table_name}_#{ideal_primary_key_name} ON #{table_name} (#{ideal_primary_key_name} ASC)"
      else
        connection.execute "ALTER TABLE `#{table_name}` ADD PRIMARY KEY (`#{ideal_primary_key_name}`)"
      end
    end
  end
  resource.reset_column_information
end

#actual_column(name) ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 119

def actual_column(name)
  resource.columns_hash[name.to_s]
end

#actual_index(name) ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 127

def actual_index(name)
  actual_indexes.detect { |actual| actual.name == name.to_s }
end

#actual_indexes ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 36

def actual_indexes
  connection.indexes table_name
end

#actual_primary_key_name ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 79

def actual_primary_key_name
  connection.primary_key(table_name).to_s
end

#column(*args) ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 59

def column(*args)
  ideal_table.column(*args)
end

#column_equivalent?(a, b) ⇒ Boolean

FIXME mysql only (assume integer primary keys)

Returns:

  • (Boolean) 


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# File 'lib/data_miner/schema.rb', line 93

def column_equivalent?(a, b)
  return false unless a and b
  a_type = a.type.to_s == 'primary_key' ? 'integer' : a.type.to_s
  b_type = b.type.to_s == 'primary_key' ? 'integer' : b.type.to_s
  a_type == b_type and a.name.to_s == b.name.to_s
end

#connection ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 20

def connection
  ActiveRecord::Base.connection
end

#description ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 40

def description
  "Define a table called #{table_name} with primary key #{ideal_primary_key_name}"
end

#ideal_column(name) ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 115

def ideal_column(name)
  ideal_table[name.to_s]
end

#ideal_index(name) ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 123

def ideal_index(name)
  ideal_indexes.detect { |ideal| ideal.name == name.to_s }
end

#ideal_indexes ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 32

def ideal_indexes
  @ideal_indexes ||= Array.new
end

#ideal_primary_key_name ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 75

def ideal_primary_key_name
  resource.primary_key.to_s
end

#ideal_table ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 28

def ideal_table
  @ideal_table ||= ActiveRecord::ConnectionAdapters::TableDefinition.new(connection)
end

#index(columns, options = {}) ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 64

def index(columns, options = {})
  options.symbolize_keys!
  columns = Array.wrap columns
  unless name = options[:name]
    default_name = connection.index_name(table_name, options.merge(:column => columns))
    name = default_name.length < MAX_INDEX_NAME_LENGTH ? default_name : default_name[0..MAX_INDEX_NAME_LENGTH-11] + Zlib.crc32(default_name).to_s
  end
  index_unique = options.has_key?(:unique) ? options[:unique] : true
  ideal_indexes.push ActiveRecord::ConnectionAdapters::IndexDefinition.new(table_name, name, index_unique, columns)
end

#index_equivalent?(a, b) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/data_miner/schema.rb', line 84

def index_equivalent?(a, b)
  return false unless a and b
  INDEX_PROPERTIES.all? do |property|
    DataMiner.log_debug "...comparing #{a.send(property).inspect}.to_s <-> #{b.send(property).inspect}.to_s"
    a.send(property).to_s == b.send(property).to_s
  end
end

#inspect ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 44

def inspect
  "Schema(#{resource}): #{description}"
end

#place_column(name) ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 131

def place_column(name)
  remove_column name if actual_column name
  ideal = ideal_column name
  DataMiner.log_debug "ADDING COLUMN #{name}"
  connection.add_column table_name, name, ideal.type.to_sym # symbol type!
  resource.reset_column_information
end

#place_index(name) ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 145

def place_index(name)
  remove_index name if actual_index name
  ideal = ideal_index name
  DataMiner.log_debug "ADDING INDEX #{name}"
  connection.add_index table_name, ideal.columns, :name => ideal.name
  resource.reset_column_information
end

#remove_column(name) ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 139

def remove_column(name)
  DataMiner.log_debug "REMOVING COLUMN #{name}"
  connection.remove_column table_name, name
  resource.reset_column_information
end

#remove_index(name) ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 153

def remove_index(name)
  DataMiner.log_debug "REMOVING INDEX #{name}"
  connection.remove_index table_name, :name => name
  resource.reset_column_information
end

#run(run) ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 159

def run(run)
  _add_extra_columns
  _create_table
  _set_primary_key
  _remove_columns
  _add_columns
  _remove_indexes
  _add_indexes
  DataMiner.log_debug "ran #{inspect}"
end

#table_name ⇒ Object 



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# File 'lib/data_miner/schema.rb', line 24

def table_name
  resource.table_name
end