Because you know that the /u04 file system has at least 100MB free, you specify /u04/oradata as
the directory and xport2.dbf as the filename, although the filename itself need not contain the
tablespace name. In addition, you set the file size to 100MB and do not click the check box for
AUTOEXTEND.
After clicking Continue and then Apply, you see the Update Message and the new size of the
XPORT tablespace??™s datafiles, as shown in Figure 4-9.
Dropping a Datafile from a Tablespace
In previous versions of Oracle, dropping a datafile from a tablespace was problematic; there was
not a single command you could issue to drop a datafile unless you dropped the entire tablespace.
You only had three alternatives:
Live with it.
Shrink it and turn off AUTOEXTEND.
Create a new tablespace, move all the objects to the new tablespace, and drop the
original tablespace.
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FIGURE 4-8 Adding a datafile to the XPORT tablespace
Chapter 4: Physical Database Layouts and Storage Management 85
Although creating a new tablespace was the most ideal from a maintenance and metadata
point of view, performing the steps involved was error-prone and involved some amount of
downtime for the tablespace, impacting availability.
Using EM Database Control, you can drop a datafile and minimize downtime, and let EM
Database Control generate the scripts for you. Following our previous example when we
expanded the XPORT tablespace by adding a datafile, I??™ll step through an example of how you
can remove the datafile by reorganizing the tablespace.
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