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Question and Answer

Connor McDonald

Thanks for the question, Sivaperumal.

Asked: September 07, 2017 - 3:19 am UTC

Last updated: September 07, 2017 - 12:06 pm UTC

Version: ORACLE 12C

Viewed 1000+ times

You Asked

Hi Team,

We are doing a migration from DB2 (Mainframe-z/OS) to Oracle 12c. There are some columns in DB2 with CLOB DATATYPE. When is migrated(Only DDL ) by Siebel application those were created as LONG. We are suggesting the team to go with CLOB as oracle is not recommending for LONG. The maximum data length is only 40K. Will there be any performance issue as the data length is not huge. Is it possible to specify the length for CLOB at table level.

REgards
Sivaperumal R

and Connor said...

I'd recommend against using LONG ... period.


And it's an easy fix

SQL> create table t ( x int, y long );

Table created.

SQL>
SQL> desc t
 Name                                                                    Null?    Type
 ----------------------------------------------------------------------- -------- -------------------------
 X                                                                                NUMBER(38)
 Y                                                                                LONG

SQL>
SQL> insert into t
  2  select rownum, object_name
  3  from dba_objects;

78275 rows created.

SQL>
SQL> alter table t modify y clob;

Table altered.

SQL>
SQL> desc t
 Name                                                                    Null?    Type
 ----------------------------------------------------------------------- -------- -------------------------
 X                                                                                NUMBER(38)
 Y                                                                                CLOB




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