A couple of database scripts

Here's a couple of scripts that I thought you might be interested in.

The first returns the current size of the database in gigabytes, rounded to two decimal places. It ignores the TEMP and the UNDO segments.

SELECT ROUND(SUM(BYTES)/1024/1024/1024,2) DB_SIZE
FROM DBA_SEGMENTS
WHERE SEGMENT_TYPE NOT IN ('TYPE2 UNDO','TEMPORARY');

The second displays a list of the segments that you have. Using this list you can identify the UNDO segment(s) that you supply to the above script.

SELECT DISTINCT SEGMENT_TYPE FROM DBA_SEGMENTS;