1. 1 © 2010 Julian Dyke Edition-Based Redefinition Julian Dyke Independent Consultant juliandyke.com Web Version

2. © 2010 Julian Dyke juliandyke.com 2 Edition-Based Redefinition Overview  Introduced in Oracle 11.2  Online Application Upgrade  Goals are:  Installation of upgrade into production database is invisible to current users of pre-upgrade application  Transactions performed by users of pre-upgrade application visible in post-upgrade application  Transactions performed by users of post-upgrade application visible in pre-upgrade application Pre-UpgradePost-UpgradeOld EditionNew Edition Cross-Edition Triggers Schema & Code Changes

3. © 2010 Julian Dyke juliandyke.com 3 Edition-Based Redefinition Life Cycle  Pre-Upgrade  Period before upgrade commences. Only one edition used by every session  Upgrade  Create a new edition  Upgrade objects and code  Concurrent use of pre and post-upgrade edition  Pre-upgrade session continue to use pre-upgrade sessions  Changes made in new edition are not visible  Cross-edition triggers propagate data changes made in old edition to new edition and vice versa  Post Upgrade Phase  When all pre-upgrade sessions have ended pre-upgrade edition can be retired  Post upgrade edition becomes default database edition

4. © 2010 Julian Dyke juliandyke.com 4 Edition-Based Redefinition Editions  Editions are non-schema object types  Every database has at least one edition  A new edition is the child of an existing edition  Every database session uses an edition  An edition is identified by a unique name  An object has an implicit edition name  Only schema-qualified name is required  Edition part is supplied automatically by database  Initial edition is called ORA$BASE  The edition used by a session is called the current edition  Can be changed for example: ALTER SESSION SET EDITION = post_upgrade;  The default edition can be changed using: ALTER DATABASE DEFAULT EDITION = post_upgrade;

5. © 2010 Julian Dyke juliandyke.com 5 Edition-Based Redefinition Editionable Objects  The following object types are editionable  Synonyms  Views  PL/SQL objects  Packages  Procedures  Functions  Tables and indexes are not editionable

6. © 2010 Julian Dyke juliandyke.com 6 Edition-Based Redefinition Example CONNECT / AS SYSDBA CREATE EDITION edition2 AS CHILD OF ORA$BASE;  Grant use of edition to users ALTER USER user1 ENABLE EDITIONS; GRANT USE ON EDITION edition2 TO user1;  Allow USER1 to work with editions  Allow USER1 to work with EDITION2  Note that an edition can only have one child

7. © 2010 Julian Dyke juliandyke.com 7 Edition-Based Redefinition Example CONNECT user1/user1 CREATE OR REPLACE PROCEDURE hello IS BEGIN dbms_output.put_line ('Version 1'); END; / ALTER SESSION SET EDITION = edition2; CREATE OR REPLACE PROCEDURE hello IS BEGIN dbms_output.put_line ('Version 2'); END; / ALTER SESSION SET EDITION = ORA$BASE; EXECUTE hello; 'Version 1' ALTER SESSION SET EDITION = edition2; EXECUTE hello; 'Version 2'

8. © 2010 Julian Dyke juliandyke.com 8 Edition-Based Redefinition Editioning Views  Tables and indexes are non-editionable  Due to amount of data  Multiple copies across editions would consume too much space  Editioning views  New type of view in Oracle 11.2 and above  Logically presents different views of a table across different editions  Use keyword EDITIONING during creation  Can be associated with same types of triggers as base tables CREATE OR REPLACE EDITIONING VIEW view1 AS SELECT * FROM t1;  To list editioning views SELECT owner,view_name FROM dba_views WHERE editioning_view = 'Y';

9. © 2010 Julian Dyke juliandyke.com 9 Edition-Based Redefinition Cross-Edition Triggers  Actual objects in the post-upgrade edition  Can be  forward  reverse  Forward cross-edition triggers  Fired by application DML issued by sessions using pre-upgrade edition  Transforms changes made to pre-upgrade columns into changes to post- upgrade columns  Reverse cross-edition triggers  Optional but recommended  Fired by application DML issued by sessions using post-upgrade edition  Transforms changes made to post-upgrade columns into changes to pre- upgrade columns

10. © 2010 Julian Dyke juliandyke.com 10 Edition-Based Redefinition Example  Create edition and grant privileges to USER1 CONNECT / AS SYSDBA ALTER USER user1 ENABLE EDITIONS; CREATE EDITION edition2; GRANT USE ON EDITION edition2 TO user1; CONNECT user1/user1 ALTER TABLE driver RENAME TO driver_;  Rename table  Create editioning view on table CONNECT user1/user1 CREATE EDITIONING VIEW driver AS SELECT driver_key, driver_name, driver_dob, country_key FROM driver_;

11. © 2010 Julian Dyke juliandyke.com 11 Edition-Based Redefinition Example  In new edition modify underlying table CONNECT user1/user1 ALTER SESSION SET EDITION = edition2; ALTER TABLE driver_ ADD driver_first_name VARCHAR2(30); ALTER TABLE driver_ ADD driver_last_name VARCHAR2(30);  In new edition create new version of editioning view: CONNECT user1/user1 CREATE OR REPLACE EDITIONING VIEW driver AS SELECT driver_key, driver_name, driver_dob, country_key, driver_first_name,driver_last_name FROM driver_;

12. © 2010 Julian Dyke juliandyke.com 12 Edition-Based Redefinition Example  In new edition create FORWARD trigger ALTER SESSION SET EDITION = edition2; CREATE OR REPLACE TRIGGER driver_forward BEFORE INSERT OR UPDATE ON driver_ FOR EACH ROW FORWARD CROSSEDITION DISABLE BEGIN :new.driver_first_name := SUBSTR (:new.driver_name,1,INSTR (:new.driver_name,' ')); :new.driver_last_name := SUBSTR (:new.driver_name,INSTR (:new.driver_name,' ') + 1); END; / ALTER SESSION SET EDITION = edition2; ALTER TRIGGER driver_forward ENABLE;  In new edition enable FORWARD trigger

13. © 2010 Julian Dyke juliandyke.com 13 Edition-Based Redefinition Example  In new edition create REVERSE trigger ALTER SESSION SET EDITION = edition2; CREATE OR REPLACE TRIGGER driver_reverse BEFORE INSERT OR UPDATE ON driver_ FOR EACH ROW REVERSE CROSSEDITION DISABLE BEGIN :new.driver_name := :new.driver_first_name||' '||:new.driver_last_name; END; / ALTER SESSION SET EDITION = edition2; ALTER TRIGGER driver_reverse ENABLE;  In new edition enable REVERSE trigger

14. © 2010 Julian Dyke juliandyke.com 14 Edition-Based Redefinition Example  In the new edition use the forward trigger to populate the values in the new columns: ALTER SESSION SET EDITION = edition2; DECLARE c NUMBER := dbms_sql.open_cursor (); x NUMBER; BEGIN dbms_sql.parse ( c => c, language_flag => DBMS_SQL.NATIVE, statement => 'UPDATE driver SET driver_key = driver_key', apply_crossedition_trigger => 'DRIVER_FORWARD' ); x := DBMS_SQL.EXECUTE (c); DBMS_SQL.CLOSE_CURSOR (c); END; /

15. © 2010 Julian Dyke juliandyke.com 15 Edition-Based Redefinition Example  In the original edition insert a new row ALTER SESSION SET EDITION = edition1; INSERT INTO driver (driver_key,driver_name,driver_dob,country_code) VALUES ('JBUT','Jenson Button',NULL,'GBR');  In the new edition check that the cross edition trigger has fired ALTER SESSION SET EDITION = edition2; SELECT driver_first_name, driver_last_name FROM driver WHERE driver_key = 'JBUT'; DRIVER_FIRST_NAMEDRIVER_LAST_NAME JensonButton

16. © 2010 Julian Dyke juliandyke.com 16 Edition-Based Redefinition Example  In the new edition insert a new row: ALTER SESSION SET EDITION = edition2; INSERT INTO driver (driver_key,driver_first_name,driver_last_name,driver_dob,country_code) VALUES ('JBUT','Jenson','Button',NULL,'GBR');  In the old edition check that the cross edition trigger has fired ALTER SESSION SET EDITION = ORA$BASE; SELECT driver_name FROM driver WHERE driver_key = 'JBUT'; DRIVER_NAME Jenson Button

17. © 2010 Julian Dyke juliandyke.com 17 Edition-Based Redefinition Cross-Edition Triggers  Cross edition triggers may include FOLLOWS and PRECEDES clauses  FOLLOWS clause  May be specified on a FORWARD cross-edition trigger or a non cross- edition trigger  Indicates trigger should be executed after a specified trigger  If trigger B specifies trigger A in its FOLLOWS clause then trigger B executes immediately after trigger A  PRECEDES clause  May only be specified on a REVERSE cross-edition trigger  Indicates trigger should be executed before a specified trigger  If trigger B specifies trigger A in its PRECEDES clause then trigger A executes immediately after trigger B

18. © 2010 Julian Dyke juliandyke.com 18 Thank you for your interest info@juliandyke.com