v$datafile视图中存储的是有关数据文件的信息，v$tempfile视图中存储的是有关临时文件的信息。在两个视图中都有file#字段，先来看一下官方文档的定义：
V$DATAFILE
This view contains datafile information from the control file.
See Also:
"V$DATAFILE_HEADER", which displays information from datafile headers| Column | Datatype | Description |
|---|---|---|
| FILE# | NUMBER | File identification number |
| CREATION_CHANGE# | NUMBER | Change number at which the datafile was created |
| CREATION_TIME | DATE | Timestamp of the datafile creation |
| TS# | NUMBER | Tablespace number |
| RFILE# | NUMBER | Tablespace relative datafile number |
| STATUS | VARCHAR2(7) | Type of file (system or user) and its status. Values: OFFLINE, ONLINE, SYSTEM, RECOVER, SYSOFF (an offline file from the SYSTEM tablespace) |
| ENABLED | VARCHAR2(10) | Describes how accessible the file is from SQL: DISABLED - No SQL access allowed READ ONLY - No SQL updates allowed READ WRITE - Full access allowed UNKNOWN - should not occur unless the control file is corrupted |
| CHECKPOINT_CHANGE# | NUMBER | SCN at last checkpoint |
| CHECKPOINT_TIME | DATE | Timestamp of the checkpoint# |
| UNRECOVERABLE_CHANGE# | NUMBER | Last unrecoverable change number made to this datafile. If the database is in ARCHIVELOG mode, then this column is updated when an unrecoverable operation completes. If the database is not in ARCHIVELOG mode, this column does not get updated. |
| UNRECOVERABLE_TIME | DATE | Timestamp of the last unrecoverable change. This column is updated only if the database is in ARCHIVELOG mode. |
| LAST_CHANGE# | NUMBER | Last change number made to this datafile (null if the datafile is being changed) |
| LAST_TIME | DATE | Timestamp of the last change |
| OFFLINE_CHANGE# | NUMBER | Offline change number of the last offline range. This column is updated only when the datafile is brought online. |
| ONLINE_CHANGE# | NUMBER | Online change number of the last offline range |
| ONLINE_TIME | DATE | Online timestamp of the last offline range |
| BYTES | NUMBER | Current datafile size (in bytes); 0 if inaccessible |
| BLOCKS | NUMBER | Current datafile size (in blocks); 0 if inaccessible |
| CREATE_BYTES | NUMBER | Size when created (in bytes) |
| BLOCK_SIZE | NUMBER | Block size of the datafile |
| NAME | VARCHAR2(513) | Name of the datafile |
| PLUGGED_IN | NUMBER | Describes whether the tablespace is plugged in. The value is 1 if the tablespace is plugged in and has not been made read/write, 0 if not. |
| BLOCK1_OFFSET | NUMBER | Offset from the beginning of the file to where the Oracle generic information begins. The exact length of the file can be computed as follows:BYTES + BLOCK1_OFFSET. |
| AUX_NAME | VARCHAR2(513) | Auxiliary name that has been set for this file via CONFIGURE AUXNAME |
| FIRST_NONLOGGED_SCN | NUMBER | First nonlogged SCN |
| FIRST_NONLOGGED_TIME | DATE | First nonlogged time |
V$TEMPFILE
This view displays tempfile information.
| Column | Datatype | Description |
|---|---|---|
| FILE# | NUMBER | Absolute file number |
| CREATION_CHANGE# | NUMBER | Creation System Change Number (SCN) |
| CREATION_TIME | DATE | Creation time |
| TS# | NUMBER | Tablespace number |
| RFILE# | NUMBER | Relative file number in the tablespace |
| STATUS | VARCHAR2(7) | Status of the file (OFFLINE|ONLINE) |
| ENABLED | VARCHAR2(10) | Enabled for read and/or write |
| BYTES | NUMBER | Size of the file in bytes (from the file header) |
| BLOCKS | NUMBER | Size of the file in blocks (from the file header) |
| CREATE_BYTES | NUMBER | Creation size of the file (in bytes) |
| BLOCK_SIZE | NUMBER | Block size for the file |
| NAME | VARC |