Class: DataMapper::Migration

Inherits:
Object
  • Object
show all
Includes:
SQL
Defined in:
lib/dm-migrations/migration.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(position, name, options = {}, &block) ⇒ Migration

Creates a new migration.

Parameters:

  • position (Symbol, String, Integer) —

    The position or version the migration belongs to.

  • name (Symbol) —

    The name of the migration.

  • options (Hash) (defaults to: {}) —

    Additional options for the migration.

Options Hash (options):

  • :verbose (Boolean) — default: true —

    Enables or disables verbose output.

  • :repository (Symbol) — default: :default —

    The DataMapper repository the migration will operate on.



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# File 'lib/dm-migrations/migration.rb', line 37

def initialize(position, name, options = {}, &block)
  @position    = position
  @name        = name
  @options     = options
  @verbose     = options.fetch(:verbose, true)
  @up_action   = nil
  @down_action = nil

  @repository = if options.key?(:database)
    warn 'Using the :database option with migrations is deprecated, use :repository instead'
    options[:database]
  else
    options.fetch(:repository, :default)
  end

  instance_eval(&block)
end

Instance Attribute Details

#name ⇒ Object (readonly)

The name of the migration



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# File 'lib/dm-migrations/migration.rb', line 14

def name
  @name
end

#position ⇒ Object (readonly)

The position or version the migration belongs to



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# File 'lib/dm-migrations/migration.rb', line 11

def position
  @position
end

#repository ⇒ Object (readonly)

The repository the migration operates on



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# File 'lib/dm-migrations/migration.rb', line 17

def repository
  @repository
end

Instance Method Details

#<=>(other) ⇒ Object

Orders migrations by position, so we know what order to run them in. First order by position, then by name, so at least the order is predictable.



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# File 'lib/dm-migrations/migration.rb', line 173

def <=> other
  if self.position == other.position
    self.name.to_s <=> other.name.to_s
  else
    self.position <=> other.position
  end
end

#adapter ⇒ DataMapper::Adapter

The adapter the migration will use.

Returns:

  • (DataMapper::Adapter) —

    The adapter the migration will operate on.

Since:

  • 1.0.1



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# File 'lib/dm-migrations/migration.rb', line 78

def adapter
  setup! unless setup?

  @adapter
end

#create_index(table_name, *columns_and_options) ⇒ Object 



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# File 'lib/dm-migrations/migration.rb', line 155

def create_index(table_name, *columns_and_options)
  if columns_and_options.last.is_a?(Hash)
    opts = columns_and_options.pop
  else
    opts = {}
  end
  columns = columns_and_options.flatten

  opts[:name] ||= "#{opts[:unique] ? 'unique_' : ''}index_#{table_name}_#{columns.join('_')}"

  execute DataMapper::Ext::String.compress_lines(<<-SQL)
    CREATE #{opts[:unique] ? 'UNIQUE ' : '' }INDEX #{quote_column_name(opts[:name])} ON
    #{quote_table_name(table_name)} (#{columns.map { |c| quote_column_name(c) }.join(', ') })
  SQL
end

#create_migration_info_table_if_needed ⇒ Object 



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# File 'lib/dm-migrations/migration.rb', line 214

def create_migration_info_table_if_needed
  save, @verbose = @verbose, false
  unless migration_info_table_exists?
    execute("CREATE TABLE #{migration_info_table} (#{migration_name_column} VARCHAR(255) UNIQUE)")
  end
  @verbose = save
end

#create_table(table_name, opts = {}, &block) ⇒ Object 



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# File 'lib/dm-migrations/migration.rb', line 141

def create_table(table_name, opts = {}, &block)
  execute TableCreator.new(adapter, table_name, opts, &block).to_sql
end

#database ⇒ Symbol?

Deprecated.

Use #repository instead.

The repository the migration will operate on.

Returns:

  • (Symbol, nil) —

    The name of the DataMapper repository the migration will run against.

Since:

  • 1.0.1.



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# File 'lib/dm-migrations/migration.rb', line 65

def database
  warn "Using the DataMapper::Migration#database method is deprecated, use #repository instead"
  @repository
end

#down(&block) ⇒ Object

define the actions that should be performed on a down migration



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# File 'lib/dm-migrations/migration.rb', line 90

def down(&block)
  @down_action = block
end

#drop_table(table_name, opts = {}) ⇒ Object 



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# File 'lib/dm-migrations/migration.rb', line 145

def drop_table(table_name, opts = {})
  execute "DROP TABLE #{adapter.send(:quote_name, table_name.to_s)}"
end

#execute(sql, *bind_values) ⇒ Object

execute raw SQL



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# File 'lib/dm-migrations/migration.rb', line 135

def execute(sql, *bind_values)
  say_with_time(sql) do
    adapter.execute(sql, *bind_values)
  end
end

#migration_info_table ⇒ Object

Quoted table name, for the adapter



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# File 'lib/dm-migrations/migration.rb', line 250

def migration_info_table
  @migration_info_table ||= quote_table_name('migration_info')
end

#migration_info_table_exists? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/dm-migrations/migration.rb', line 227

def migration_info_table_exists?
  adapter.storage_exists?('migration_info')
end

#migration_name_column ⇒ Object

Quoted ‘migration_name` column, for the adapter



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# File 'lib/dm-migrations/migration.rb', line 255

def migration_name_column
  @migration_name_column ||= quote_column_name('migration_name')
end

#migration_record ⇒ Object

Fetch the record for this migration out of the migration_info table



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# File 'lib/dm-migrations/migration.rb', line 232

def migration_record
  return [] unless migration_info_table_exists?
  adapter.select("SELECT #{migration_name_column} FROM #{migration_info_table} WHERE #{migration_name_column} = #{quoted_name}")
end

#modify_table(table_name, opts = {}, &block) ⇒ Object 



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# File 'lib/dm-migrations/migration.rb', line 149

def modify_table(table_name, opts = {}, &block)
  TableModifier.new(adapter, table_name, opts, &block).statements.each do |sql|
    execute(sql)
  end
end

#needs_down? ⇒ Boolean

True if the migration has already been run

Returns:

  • (Boolean) 


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# File 'lib/dm-migrations/migration.rb', line 244

def needs_down?
  return false unless migration_info_table_exists?
  ! migration_record.empty?
end

#needs_up? ⇒ Boolean

True if the migration needs to be run

Returns:

  • (Boolean) 


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# File 'lib/dm-migrations/migration.rb', line 238

def needs_up?
  return true unless migration_info_table_exists?
  migration_record.empty?
end

#perform_down ⇒ Object

un-do the migration by running the code in the #down block



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# File 'lib/dm-migrations/migration.rb', line 115

def perform_down
  result = nil

  if needs_down?
    # TODO: fix this so it only does transactions for databases that support create/drop
    # database.transaction.commit do
    if @down_action
      say_with_time "== Performing Down Migration ##{position}: #{name}", 0 do
        result = @down_action.call
      end
    end

    update_migration_info(:down)
    # end
  end

  result
end

#perform_up ⇒ Object

perform the migration by running the code in the #up block



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# File 'lib/dm-migrations/migration.rb', line 95

def perform_up
  result = nil

  if needs_up?
    # TODO: fix this so it only does transactions for databases that support create/drop
    # database.transaction.commit do
    if @up_action
      say_with_time "== Performing Up Migration ##{position}: #{name}", 0 do
        result = @up_action.call
      end
    end

    update_migration_info(:up)
    # end
  end

  result
end

#quote_column_name(column_name) ⇒ Object 



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# File 'lib/dm-migrations/migration.rb', line 264

def quote_column_name(column_name)
  # TODO: Fix this for 1.9 - can't use this hack to access a private method
  adapter.send(:quote_name, column_name.to_s)
end

#quote_table_name(table_name) ⇒ Object 



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# File 'lib/dm-migrations/migration.rb', line 259

def quote_table_name(table_name)
  # TODO: Fix this for 1.9 - can't use this hack to access a private method
  adapter.send(:quote_name, table_name.to_s)
end

#quoted_name ⇒ Object

Quote the name of the migration for use in SQL



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# File 'lib/dm-migrations/migration.rb', line 223

def quoted_name
  "'#{name}'"
end

#say(message, indent = 4) ⇒ Object

Output some text. Optional indent level



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# File 'lib/dm-migrations/migration.rb', line 182

def say(message, indent = 4)
  write "#{" " * indent} #{message}"
end

#say_with_time(message, indent = 2) ⇒ Object

Time how long the block takes to run, and output it with the message.



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# File 'lib/dm-migrations/migration.rb', line 187

def say_with_time(message, indent = 2)
  say(message, indent)
  result = nil
  time = Benchmark.measure { result = yield }
  say("-> %.4fs" % time.real, indent)
  result
end

#up(&block) ⇒ Object

define the actions that should be performed on an up migration



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# File 'lib/dm-migrations/migration.rb', line 85

def up(&block)
  @up_action = block
end

#update_migration_info(direction) ⇒ Object

Inserts or removes a row into the ‘migration_info` table, so we can mark this migration as run, or un-done



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# File 'lib/dm-migrations/migration.rb', line 201

def update_migration_info(direction)
  save, @verbose = @verbose, false

  create_migration_info_table_if_needed

  if direction.to_sym == :up
    execute("INSERT INTO #{migration_info_table} (#{migration_name_column}) VALUES (#{quoted_name})")
  elsif direction.to_sym == :down
    execute("DELETE FROM #{migration_info_table} WHERE #{migration_name_column} = #{quoted_name}")
  end
  @verbose = save
end

#write(text = "") ⇒ Object

output the given text, but only if verbose mode is on



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# File 'lib/dm-migrations/migration.rb', line 196

def write(text="")
  puts text if @verbose
end