Tip

Reference information about v$ and other dictionary tables

Now you don't have to look in a reference manual to find descriptions about v$ and other dictionary tables and their columns -- you can write a SQL query. The sample script shown below will prompt you for the name of the table. 

SET LINESIZE 300
SET PAGESIZE 0
COLUMN TABLE_NAME FORMAT A40 WRAP
COLUMN COLUMN_NAME FORMAT A40 WRAP
COLUMN COMMENTS FORMAT A80 WRAP

This is to get information about tables. Try it by entering DBA_TABLES.

SELECT * FROM DICTIONARY
WHERE TABLE_NAME= UPPER('&TABLE_NAME');

This is to get information about columns. Try it by entering DBA_TABLES.

SELECT * FROM DICT_COLUMNS
WHERE TABLE_NAME= UPPER('&TABLE_NAME');

Reader Feedback

Edward M. writes: Here is what I get when I run this query.

Enter value for table_name: dba_tables
old   2: WHERE TABLE_NAME= UPPER('&TABLE_NAME')
new   2: WHERE TABLE_NAME= UPPER('dba_tables')
buffer overflow. Use SET command to reduce ARRAYSIZE or increase MAXDATA.
What I can I do in this case?

The author responds: Please use the following before executing the query:

SET ARRAYSIZE 1
The Following is an explanation from the SQL*PLUS manual about why we are reducing ARRAYSIZE TO 1:

"SET ARRAYSIZE sets the number of rows--called a batch--that SQL*Plus will fetch from the database at one time. Valid values are 1 to 5000. A large value increases the efficiency of queries and subqueries that fetch

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many rows, but requires more memory. Values over approximately 100 provide little added performance. ARRAYSIZE has no effect on the results of SQL*Plus operations other than increasing efficiency." I hope this helps.

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This was first published in September 2002

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