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module ActiveRecord
module ConnectionAdapters
class AbstractAdapter
class SchemaCreation # :nodoc:
def initialize(conn)
@conn = conn
@cache = {}
end
def accept(o)
m = @cache[o.class] ||= "visit_#{o.class.name.split('::').last}"
send m, o
end
def visit_AddColumn(o)
sql_type = type_to_sql(o.type, o.limit, o.precision, o.scale)
sql = "ADD #{quote_column_name(o.name)} #{sql_type}"
add_column_options!(sql, column_options(o))
end
private
def visit_AlterTable(o)
sql = "ALTER TABLE #{quote_table_name(o.name)} "
sql << o.adds.map { |col| visit_AddColumn col }.join(' ')
sql << o.foreign_key_adds.map { |fk| visit_AddForeignKey fk }.join(' ')
sql << o.foreign_key_drops.map { |fk| visit_DropForeignKey fk }.join(' ')
end
def visit_ColumnDefinition(o)
sql_type = type_to_sql(o.type, o.limit, o.precision, o.scale)
column_sql = "#{quote_column_name(o.name)} #{sql_type}"
add_column_options!(column_sql, column_options(o)) unless o.primary_key?
column_sql
end
def visit_TableDefinition(o)
create_sql = "CREATE#{' TEMPORARY' if o.temporary} TABLE "
create_sql << "#{quote_table_name(o.name)} "
create_sql << "(#{o.columns.map { |c| accept c }.join(', ')}) " unless o.as
create_sql << "#{o.options}"
create_sql << " AS #{@conn.to_sql(o.as)}" if o.as
create_sql
end
def visit_AddForeignKey(o)
sql = <<-SQL.strip_heredoc
ADD CONSTRAINT #{quote_column_name(o.name)}
FOREIGN KEY (#{quote_column_name(o.column)})
REFERENCES #{quote_table_name(o.to_table)} (#{quote_column_name(o.primary_key)})
SQL
sql << " #{action_sql('DELETE', o.on_delete)}" if o.on_delete
sql << " #{action_sql('UPDATE', o.on_update)}" if o.on_update
sql
end
def visit_DropForeignKey(name)
"DROP CONSTRAINT #{quote_column_name(name)}"
end
def column_options(o)
column_options = {}
column_options[:null] = o.null unless o.null.nil?
column_options[:default] = o.default unless o.default.nil?
column_options[:column] = o
column_options[:first] = o.first
column_options[:after] = o.after
column_options
end
def quote_column_name(name)
@conn.quote_column_name name
end
def quote_table_name(name)
@conn.quote_table_name name
end
def type_to_sql(type, limit, precision, scale)
@conn.type_to_sql type.to_sym, limit, precision, scale
end
def add_column_options!(sql, options)
sql << " DEFAULT #{quote_value(options[:default], options[:column])}" if options_include_default?(options)
# must explicitly check for :null to allow change_column to work on migrations
if options[:null] == false
sql << " NOT NULL"
end
if options[:auto_increment] == true
sql << " AUTO_INCREMENT"
end
sql
end
def quote_value(value, column)
column.sql_type ||= type_to_sql(column.type, column.limit, column.precision, column.scale)
column.cast_type ||= type_for_column(column)
@conn.quote(value, column)
end
def options_include_default?(options)
options.include?(:default) && !(options[:null] == false && options[:default].nil?)
end
def action_sql(action, dependency)
case dependency
when :nullify then "ON #{action} SET NULL"
when :cascade then "ON #{action} CASCADE"
when :restrict then "ON #{action} RESTRICT"
else
raise ArgumentError, <<-MSG.strip_heredoc
'#{dependency}' is not supported for :on_update or :on_delete.
Supported values are: :nullify, :cascade, :restrict
MSG
end
end
def type_for_column(column)
@conn.lookup_cast_type(column.sql_type)
end
end
end
end
end
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