Class: Mystic::Migration

Inherits:
Object
  • Object
show all
Defined in:
lib/mystic/migration.rb

Constant Summary collapse

Error = 
Class.new StandardError
IrreversibleError = 
Class.new StandardError

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Migration

Returns a new instance of Migration.



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# File 'lib/mystic/migration.rb', line 8

def initialize
	@irreversible = false
	@sql = ""
end

Instance Method Details

#alter_table(name) {|table| ... } ⇒ Object

Yields:

  • (table)

Raises:

  • (ArgumentError) 


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# File 'lib/mystic/migration.rb', line 67

def alter_table name
			raise ArgumentError, "No block provided, a block is required to alter a table." unless block_given?
  table = Mystic::SQL::Table.alter :name => name
  yield table
  execute table
end

#create_ext(extname) ⇒ Object 



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# File 'lib/mystic/migration.rb', line 83

def create_ext extname
  execute "CREATE EXTENSION \"#{extname.to_s}\""
end

#create_table(name) {|table| ... } ⇒ Object

Yields:

  • (table)

Raises:

  • (ArgumentError) 


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# File 'lib/mystic/migration.rb', line 60

def create_table name
  raise ArgumentError, "No block provided, a block is required to create a table." unless block_given?
  table = Mystic::SQL::Table.create :name => name
  yield table
  execute table
end

#create_view(name, sql) ⇒ Object 



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# File 'lib/mystic/migration.rb', line 91

def create_view name, sql
  execute "CREATE VIEW #{name} AS #{sql}"
end

#drop_ext(extname) ⇒ Object 



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# File 'lib/mystic/migration.rb', line 87

def drop_ext extname
  execute "DROP EXTENSION \"#{extname.to_s}\""
end

#drop_index(idx_name) ⇒ Object 



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# File 'lib/mystic/migration.rb', line 79

def drop_index idx_name
    execute "DROP INDEX #{idx_name}"
end

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



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# File 'lib/mystic/migration.rb', line 74

def drop_table name, opts={}
			irreversible!
  execute "DROP TABLE #{name} #{opts[:cascade] ? "CASCADE" : "RESTRICT" }"
end

#drop_view(name) ⇒ Object 



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# File 'lib/mystic/migration.rb', line 95

def drop_view name
  execute "DROP VIEW #{name}"
end

#exec_migration(direction) ⇒ Object 



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# File 'lib/mystic/migration.rb', line 37

def exec_migration direction
    sql = to_sql direction
	Mystic.postgres.execute sql
end

#execute(obj) ⇒ Object

All migration SQL goes through here



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# File 'lib/mystic/migration.rb', line 48

def execute obj
			@sql << obj.to_s.sql_terminate # to_sql isn't defined for strings, to_sql is aliased to to_s
end

#irreversible! ⇒ Object 



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# File 'lib/mystic/migration.rb', line 52

def irreversible!
	@irreversible = true
end

#irreversible? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/mystic/migration.rb', line 56

def irreversible?
	@irreversible
end

#migrate ⇒ Object 



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# File 'lib/mystic/migration.rb', line 13

def migrate
	exec_migration :up
end

#rollback ⇒ Object 



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# File 'lib/mystic/migration.rb', line 17

def rollback
	exec_migration :down
end

#to_sql(direction) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/mystic/migration.rb', line 21

def to_sql direction
  @sql = ""
			_direction = direction.to_sym
			
			raise ArgumentError, "Direction must be either :up or :down." unless [:up, :down].include? _direction
			raise IrreversibleError, "Impossible to roll back an irreversible migration." if _direction == :down && irreversible?
			
  execute "BEGIN"
			method(_direction).call
  execute "COMMIT"
  
  res = @sql.dup
  @sql = ""
  res
end