PI77719: ALLOW A USER TO EXPLICITLY DEFINE A HIDDEN ROWID COLUMN (PART 2)

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• This APAR introduces new functionality to allow users to
  explicitly define a (partially) hidden ROWID column.
  (This APAR provides enablement support. Toleration support is
  shipped via a separate APAR PI77718.)
  

Local fix

• N/A
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: DB2 11 for z/OS users of ROWID columns       *
  ****************************************************************
  * PROBLEM DESCRIPTION: There is a need to allow users to       *
  *                      explicitly define a hidden ROWID column *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  DB2 implicitly generates a hidden ROWID column when a table is
  created with a LOB column or altered to add a LOB column and the
  user does not explicitly define a ROWID column. The advantage of
  a hidden (ROWID) column is that such a column is not included
  when an application uses the SELECT * construct.
  
  Currently, users cannot explicitly define a hidden ROWID column.
  Any attempt to explicitly define a hidden ROWID column (using
  the IMPLICITLY HIDDEN clause) will return SQLCODE -270. This
  limitation makes it impossible to use a ROWID column and hide it
  from applications when no LOBs are involved. A possible use case
  could be to use a ROWID column as a partitioning column to
  spread inserts across partitions and hide it to minimize the
  impact on (existing) applications.
  

Problem conclusion

Temporary fix

Comments

• PI77719 enables function to allow users to explicitly define a
  hidden ROWID column with a CREATE TABLE statement in
  new function mode. Enabling APAR PI77719 requires
  pre-conditioning APAR PI77718 to be applied to all members of a
  data sharing group prior to PI77719's application. In a
  coexistence environment, this APAR also requires DB2 12
  pre-conditioning APAR PI76972 to be applied to all DB2 12
  members prior to PI77719's application.
  
  External changes include, but are not limited to:
  - CREATE TABLE processing will be modified to allow specifying
    the IMPLICITLY HIDDEN clause for ROWID columns.
  - ALTER TABLE processing will be modified to support dropping an
    explicitly defined hidden ROWID column under specific
    conditions.
  - The SYSIBM.SYSCOLUMNS.HIDDEN column will be populated with a
    value of 'R' to indicate ROWID columns that were explicitly
    defined with the IMPLICITLY HIDDEN attribute.
  
  PI77310 is the DB2 12 version of this APAR.
  
  PI77360 is a related APAR that is recommended for users of
  metadata stored procedures SYSIBM.SQLPSEUDOCOLUMNS and
  SYSIBM.SQLSPECIALCOLUMNS. It updates the stored procedures to
  include support for explicitly defined hidden ROWID columns.
  Refer to PI77360's description for more information.
  
  Additional Keywords:
  SQLCREATE
  

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UI47230

Modules/Macros

• DSNXICB3
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RB10 PSY UI47230

     UP17/06/01 P F705

Fix is available

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