The ALTER DATABASE MOVE DATAFILE command relocates a data file to a new location while the database remains online, introduced in Oracle 12c and enhanced in subsequent releases like 23ai. Let’s evaluate each option:
A. DML may be performed on tables with one or more extents in this data file during the execution of this command.True. The move operation is online by default in Oracle 23ai, allowing DML (INSERT, UPDATE, DELETE) operations on tables within the data file being moved. The database ensures consistency using redo and undo mechanisms.
B. It overwrites any existing file with the name sales02.dbf in /u02 by default.False. By default, the command does not overwrite an existing file unless the REUSE clause is specified (e.g., ALTER DATABASE MOVE DATAFILE ... REUSE). Without it, the command fails if the target file exists.
C. The "TO" clause containing the new file name must be specified even if Oracle Managed Files (OMF) is used.False. When OMF is enabled (via DB_CREATE_FILE_DEST), the TO clause is optional. If omitted, Oracle automatically generates a file name and places it in the OMF destination.
D. Compressed objects in sales01.dbf will be uncompressed in sales02.dbf after the move.False. The move operation is a physical relocation of the data file; it does not alter the logical structure or compression state of objects within it. Compressed data remains compressed.
E. Tables with one or more extents in this data file may be queried during the execution of this command.True. The online nature of the move allows queries (SELECT statements) to proceed without interruption, leveraging Oracle’s multi-version consistency model.
[References:Oracle Database Administrator’s Guide 23ai, Chapter "Managing Data Files and Temp Files," Section "Moving Data Files Online.", , ]
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