class ActiveRecord::ConnectionAdapters::AbstractMysqlAdapter

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 332
def begin_db_transaction
  execute "BEGIN"
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 336
def begin_isolated_db_transaction(isolation)
  execute "SET TRANSACTION ISOLATION LEVEL #{transaction_isolation_levels.fetch(isolation)}"
  begin_db_transaction
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 659
def case_insensitive_comparison(table, attribute, column, value)
  if column.case_sensitive?
    super
  else
    table[attribute].eq(value)
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 651
def case_sensitive_comparison(table, attribute, column, value)
  if column.case_sensitive?
    table[attribute].eq(value)
  else
    super
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 646
def case_sensitive_modifier(node, table_attribute)
  node = Arel::Nodes.build_quoted node, table_attribute
  Arel::Nodes::Bin.new(node)
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 528
def change_column_null(table_name, column_name, null, default = nil)
  column = column_for(table_name, column_name)

  unless null || default.nil?
    execute("UPDATE #{quote_table_name(table_name)} SET #{quote_column_name(column_name)}=#{quote(default)} WHERE #{quote_column_name(column_name)} IS NULL")
  end

  change_column table_name, column_name, column.sql_type, :null => null
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 404
def charset
  show_variable 'character_set_database'
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 310
def clear_cache!
  super
  reload_type_map
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 409
def collation
  show_variable 'collation_database'
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 383
def create_database(name, options = {})
  if options[:collation]
    execute "CREATE DATABASE `#{name}` DEFAULT CHARACTER SET `#{options[:charset] || 'utf8'}` COLLATE `#{options[:collation]}`"
  else
    execute "CREATE DATABASE `#{name}` DEFAULT CHARACTER SET `#{options[:charset] || 'utf8'}`"
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 399
def current_database
  select_value 'SELECT DATABASE() as db'
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 509
def drop_table(table_name, options = {})
  execute "DROP#{' TEMPORARY' if options[:temporary]} TABLE #{quote_table_name(table_name)}#{' CASCADE' if options[:force] == :cascade}"
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 361
def empty_insert_statement_value
  "VALUES ()"
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 316
def execute(sql, name = nil)
  log(sql, name) { @connection.query(sql) }
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 552
      def foreign_keys(table_name)
        fk_info = select_all "          SELECT fk.referenced_table_name as 'to_table'
                ,fk.referenced_column_name as 'primary_key'
                ,fk.column_name as 'column'
                ,fk.constraint_name as 'name'
          FROM information_schema.key_column_usage fk
          WHERE fk.referenced_column_name is not null
            AND fk.table_schema = '#{@config[:database]}'
            AND fk.table_name = '#{table_name}'
".strip_heredoc

        create_table_info = select_one("SHOW CREATE TABLE #{quote_table_name(table_name)}")["Create Table"]

        fk_info.map do |row|
          options = {
            column: row['column'],
            name: row['name'],
            primary_key: row['primary_key']
          }

          options[:on_update] = extract_foreign_key_action(create_table_info, row['name'], "UPDATE")
          options[:on_delete] = extract_foreign_key_action(create_table_info, row['name'], "DELETE")

          ForeignKeyDefinition.new(table_name, row['to_table'], options)
        end
      end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 229
def index_algorithms
  { default: 'ALGORITHM = DEFAULT', copy: 'ALGORITHM = COPY', inplace: 'ALGORITHM = INPLACE' }
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 225
def native_database_types
  NATIVE_DATABASE_TYPES
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 628
def pk_and_sequence_for(table)
  execute_and_free("SHOW CREATE TABLE #{quote_table_name(table)}", 'SCHEMA') do |result|
    create_table = each_hash(result).first[:"Create Table"]
    if create_table.to_s =~ /PRIMARY KEY\s+(?:USING\s+\w+\s+)?\((.+)\)/
      keys = $1.split(",").map { |key| key.delete('`"') }
      keys.length == 1 ? [keys.first, nil] : nil
    else
      nil
    end
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 641
def primary_key(table)
  pk_and_sequence = pk_and_sequence_for(table)
  pk_and_sequence && pk_and_sequence.first
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 285
def quoted_date(value)
  if supports_datetime_with_precision? && value.acts_like?(:time) && value.respond_to?(:usec)
    "#{super}.#{sprintf("%06d", value.usec)}"
  else
    super
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 277
def quoted_false
  QUOTED_FALSE
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 269
def quoted_true
  QUOTED_TRUE
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 369
def recreate_database(name, options = {})
  drop_database(name)
  sql = create_database(name, options)
  reconnect!
  sql
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 513
def rename_index(table_name, old_name, new_name)
  if supports_rename_index?
    validate_index_length!(table_name, new_name)

    execute "ALTER TABLE #{quote_table_name(table_name)} RENAME INDEX #{quote_table_name(old_name)} TO #{quote_table_name(new_name)}"
  else
    super
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 504
def rename_table(table_name, new_name)
  execute "RENAME TABLE #{quote_table_name(table_name)} TO #{quote_table_name(new_name)}"
  rename_table_indexes(table_name, new_name)
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 57
def schema_creation
  SchemaCreation.new self
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 620
def show_variable(name)
  variables = select_all("select @@#{name} as 'Value'", 'SCHEMA')
  variables.first['Value'] unless variables.empty?
rescue ActiveRecord::StatementInvalid
  nil
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 682
def strict_mode?
  self.class.type_cast_config_to_boolean(@config.fetch(:strict, true))
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 221
def supports_datetime_with_precision?
  version >= '5.6.4'
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 213
def supports_foreign_keys?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 197
def supports_index_sort_order?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 209
def supports_indexes_in_create?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 183
def supports_migrations?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 187
def supports_primary_key?
  true
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 205
def supports_transaction_isolation?
  version >= '5.0.0'
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 217
def supports_views?
  version >= '5.0.0'
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 428
def table_exists?(name)
  return false unless name.present?
  return true if tables(nil, nil, name).any?

  name          = name.to_s
  schema, table = name.split('.', 2)

  unless table # A table was provided without a schema
    table  = schema
    schema = nil
  end

  tables(nil, schema, table).any?
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 424
def truncate(table_name, name = nil)
  execute "TRUNCATE TABLE #{quote_table_name(table_name)}", name
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 581
def type_to_sql(type, limit = nil, precision = nil, scale = nil)
  case type.to_s
  when 'binary'
    case limit
    when 0..0xfff;           "varbinary(#{limit})"
    when nil;                "blob"
    when 0x1000..0xffffffff; "blob(#{limit})"
    else raise(ActiveRecordError, "No binary type has character length #{limit}")
    end
  when 'integer'
    case limit
    when 1; 'tinyint'
    when 2; 'smallint'
    when 3; 'mediumint'
    when nil, 4, 11; 'int(11)'  # compatibility with MySQL default
    when 5..8; 'bigint'
    else raise(ActiveRecordError, "No integer type has byte size #{limit}")
    end
  when 'text'
    case limit
    when 0..0xff;               'tinytext'
    when nil, 0x100..0xffff;    'text'
    when 0x10000..0xffffff;     'mediumtext'
    when 0x1000000..0xffffffff; 'longtext'
    else raise(ActiveRecordError, "No text type has character length #{limit}")
    end
  when 'datetime'
    return super unless precision

    case precision
      when 0..6; "datetime(#{precision})"
      else raise(ActiveRecordError, "No datetime type has precision of #{precision}. The allowed range of precision is from 0 to 6.")
    end
  else
    super
  end
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 281
def unquoted_false
  0
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 273
def unquoted_true
  1
end

# File activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb, line 686
def valid_type?(type)
  !native_database_types[type].nil?
end