How to generate a sql script that drops all tables starting with a certain prefix

In some circumstances, you may want to drop all tables in a schema that start with certain prefix. Say for example you like drop all tables starting with the prefix 'TMP_'.

You can execute:

BEGIN
  FOR t IN ( SELECT table_name FROM user_tables WHERE table_name LIKE 'TMP_%' )
  LOOP
    EXECUTE IMMEDIATE 'DROP TABLE ' || t.table_name || ' CASCADE CONSTRAINTS';
  END LOOP;
END;

This block finds and drops all tables whose name start with 'TMP_'.

Another way is to first generate a list of drop statements, save the list as a sql script and finally execute it. Personally I like this way better since it lets me to see and be sure exactly what is going to be removed.

This block generates a list of drop statements for all tables in your schema starting with 'TMP_' :

select 'drop table ' || table_name || ' cascade constraints' || ';'
from   user_tables
where  table_name like 'TMP_%';

You can then take this generated list, save it as a sql script and execute it as you wish.

How to zip files with a pattern in name into a single zip file

To zip files with a certain pattern in their name in a directory, we can combine find and zip command like below :

find <DIRECTORY_PATH> -name \*<PATTERN>\* | zip <ZIP_FILE_NAME>.zip -@ 

Finding out tablespace size, used space and free space in Oracle database

This query which should be run as SYS or SYSTEM user, will give you the following information:

• Tablespace Name
• % used
• Space allocated to tablespace
• Space used in tablespace
• Space free in tablespace
• Number of datafiles used by tablespace

SELECT  a.tablespace_name,

    ROUND (((c.BYTES - NVL (b.BYTES, 0)) / c.BYTES) * 100,2) percentage_used,

    c.BYTES / 1024 / 1024 space_allocated,

    ROUND (c.BYTES / 1024 / 1024 - NVL (b.BYTES, 0) / 1024 / 1024,2) space_used,

    ROUND (NVL (b.BYTES, 0) / 1024 / 1024, 2) space_free, 

    c.DATAFILES

  FROM dba_tablespaces a,

       (    SELECT   tablespace_name, 

                  SUM (BYTES) BYTES

           FROM   dba_free_space

       GROUP BY   tablespace_name

       ) b,

      (    SELECT   COUNT (1) DATAFILES, 

                  SUM (BYTES) BYTES, 

                  tablespace_name

           FROM   dba_data_files

       GROUP BY   tablespace_name

    ) c

  WHERE b.tablespace_name(+) = a.tablespace_name 

    AND c.tablespace_name(+) = a.tablespace_name

ORDER BY NVL (((c.BYTES - NVL (b.BYTES, 0)) / c.BYTES), 0) DESC;

How to fix Cannot open your terminal '/dev/pts/#' - please check.

simply run :

script /dev/null

and try again.