The INFORMATION_SCHEMA FILES Table The  FILES  table provides information about  InnoDB  data files. In NDB Cluster, this table also provides information about the files in which NDB Cluster Disk Data tables are stored. For additional information specific to  InnoDB , see InnoDB Notes, later in this section; for additional information specific to NDB Cluster, see NDB Notes. The  FILES  table has these columns: • FILE_ID • FILE_NAME For  NDB : A file identifier.  FILE_ID  column values are auto-generated. For  InnoDB : The tablespace ID, also referred to as the  space_id  or  fil_space_t::id . For  InnoDB : The name of the data file. File-per-table and general tablespaces have an  .ibd  file name extension. Undo tablespaces are prefixed by  undo . The system tablespace is prefixed by  ibdata . The global temporary tablespace is prefixed by  ibtmp . The file name includes the file path, which may be relative to the MySQL data directory (the value of the  datadir  system variable). For  NDB : The name of an undo log file created by  CREATE LOGFILE GROUP  or  ALTER LOGFILE GROUP , or of a data file created by  CREATE TABLESPACE  or  ALTER TABLESPACE . In NDB 8.0, the file name is shown with a relative path; for an undo log file, this path is relative to the directory  DataDir/ ndb_NodeId_fs/LG ; for a data file, it is relative to the directory  DataDir/ndb_NodeId_fs/TS . This means, for example, that the name of a data file created with  ALTER TABLESPACE ts ADD DATAFILE ’data_2.dat’ INITIAL SIZE 256M  is shown as  ./data_2.dat . For  InnoDB : The tablespace file type. There are three possible file types for  InnoDB  files.  TABLESPACE is the file type for any system, general, or file-per-table tablespace file that holds tables, indexes, or other forms of user data.  TEMPORARY  is the file type for temporary tablespaces.  UNDO LOG  is the file type for undo tablespaces, which hold undo records. • FILE_TYPE • TABLESPACE_NAME • TABLE_CATALOG • TABLE_SCHEMA • TABLE_NAME 4792 For  InnoDB : General tablespace names are as specified when created. File-per-table tablespace names are shown in the following format:  schema_name / table_name . The  InnoDB  system tablespace name is  innodb_system . The global temporary tablespace name is  innodb_temporary . Default undo tablespace names are  innodb_undo_001  and  innodb_undo_002 . User-created undo tablespace names are as specified when created. This value is always empty. This is always  NULL . This is always  NULL . The name of the tablespace with which the file is associated. For  NDB : One of the values  UNDO LOG  or  DATAFILE . Prior to NDB 8.0.13,  TABLESPACE  was also a possible value.