Consider the following scenario:
You have a directory, data, under the disk group tdgroup
You want to create an alias for one of the data files and you execute the following command:
ALTER DISKGROUP tdgroupA
ADD ALIAS ‘+tdgroupA/data/datafile.dbf’
For ‘+tdgroupA.231.45678’;
Which task would be accomplished by the command?
A.
The command drops the file +tdgroupA.231.45678
B.
The command physically relocates the file to +tdgroupA/data and renames the file to datafile.dbf.
C.
The command creates a copy of the +tdgroupA.231.45678 file and places it in +tdgroupA/data after remaining the file to datafile.dbf.
D.
The command creates a synonym, datafile.dbf, and places it in +tdgroupA/data and does not remove the +tdgroupA.231.45678 file.
E.
The command creates a file, datafile.dbf, in +tdgroupA/ data and removes the references for +tdgroupA.231.45678 from the data dictionary views.
Explanation:
Alias names (or just “aliases”) are intended to provide a more user-friendly means of referring to ASM files, rather than using the system-generated filenames. You can create an alias for a file when you create it in the database, or you can add an alias to an existing file using the ADD ALIAS clause of the ALTER DISKGROUP statement. You can create an alias in any system-generated or user-created ASM directory. You cannot create an alias at the root level (+), however. The following statement adds a new alias name for a system-generated file name:
ALTER DISKGROUP dgroup1 ADD ALIAS ‘+dgroup1/mydir/second.dbf’
FOR ‘+dgroup1/sample/datafile/mytable.342.3’;REF.: Oracle(r) 10g Administrator Guide, 12-28