Rick -- Thanks for the question regarding "Partitioning existing tables", version 10g

Submitted on 19-May-2008 15:57 Central time zone

Tom's latest followup | Bookmark | Bottom

Last updated 28-Oct-2010 12:17

You Asked

I am attempting to partition a Table T1 with existing data.
Table T1 is as follows:

COLUMN DATATYPE
-----------------
COLUMN1 NUMBER PK
COLUMN2 NUMBER
COLUMN3 NUMBER

I am using this approach:
1- ALTER TABLE T1 RENAME TO T1_TEMP
2- CREATE TABLE T1 (
COLUMN1 NUMBER,
COLUMN2 NUMBER,
COLUMN3 NUMBER)
PARTITION BY HASH (COLUMN1)
( PARTITION P1 TABLESPACE T1,
PARTITION P2 TABLESPACE T1
);
3- INSERT INTO T1 SELECT * FROM T1_TEMP
4- DROP TABLE T1_TEMP CASCADE CONSTRAINTS

The problem with the above method is that I have tables T2, T3, Tn with a foreign key reference on COLUMN1 of T1. The reference is automatically moved to T1_TEMP but not back to T1.

QUESTION:
---------
How to modify all references to T1_TEMP to point back to T1 after having copied the data in step 3?

THANKS!

and we said...

probably the easiest, safest way will be to use dbms_redefinition - it'll copy over the grants, indexes, constraints, everything.

Table P is the parent table.

Table T1 is the existing non-partitioned table.
Table T2 is the new partitioned table.

At the end, we are left with P and T1 - T1 being partitioned.


ops$tkyte%ORA10GR2> create table p ( x primary key )
  2  as
  3  select user_id from all_users;

Table created.

ops$tkyte%ORA10GR2>
ops$tkyte%ORA10GR2> create table t1
  2  as
  3  select * from all_users
  4  /

Table created.

ops$tkyte%ORA10GR2> alter table t1 add constraint t1_pk primary key(user_id);

Table altered.

ops$tkyte%ORA10GR2> alter table t1 add constraint t1_fk foreign key(user_id) references 
p(x);

Table altered.

ops$tkyte%ORA10GR2>
ops$tkyte%ORA10GR2> create table t2
  2  ( username varchar2(30),
  3    user_id  number,
  4    created  date
  5  )
  6  partition by hash(user_id) partitions 8;

Table created.

ops$tkyte%ORA10GR2> exec dbms_redefinition.can_redef_table( user, 'T1' );

PL/SQL procedure successfully completed.

ops$tkyte%ORA10GR2>
ops$tkyte%ORA10GR2> exec dbms_redefinition.start_redef_table( user, 'T1', 'T2' );

PL/SQL procedure successfully completed.

ops$tkyte%ORA10GR2>
ops$tkyte%ORA10GR2>
ops$tkyte%ORA10GR2> variable nerrors number
ops$tkyte%ORA10GR2> begin
  2          dbms_redefinition.copy_table_dependents
  3          ( user, 'T1', 'T2',
  4            copy_indexes => dbms_redefinition.cons_orig_params,
  5            num_errors => :nerrors );
  6  end;
  7  /

PL/SQL procedure successfully completed.

ops$tkyte%ORA10GR2> exec dbms_redefinition.finish_redef_table( user, 'T1', 'T2' );

PL/SQL procedure successfully completed.

ops$tkyte%ORA10GR2>
ops$tkyte%ORA10GR2> select dbms_metadata.get_ddl( 'TABLE', 'T1' ) from dual;

DBMS_METADATA.GET_DDL('TABLE','T1')
-------------------------------------------------------------------------------

  CREATE TABLE "OPS$TKYTE"."T1"
   (    "USERNAME" VARCHAR2(30) CONSTRAINT "SYS_C0026838" NOT NULL ENABLE NOVALIDA
TE,
        "USER_ID" NUMBER CONSTRAINT "SYS_C0026839" NOT NULL ENABLE NOVALIDATE,
        "CREATED" DATE CONSTRAINT "SYS_C0026840" NOT NULL ENABLE NOVALIDATE,
         CONSTRAINT "T1_PK" PRIMARY KEY ("USER_ID")
  USING INDEX PCTFREE 10 INITRANS 2 MAXTRANS 255 COMPUTE STATISTICS
  STORAGE(INITIAL 65536 NEXT 1048576 MINEXTENTS 1 MAXEXTENTS 2147483645
  PCTINCREASE 0 FREELISTS 1 FREELIST GROUPS 1 BUFFER_POOL DEFAULT)
  TABLESPACE "USERS"  ENABLE NOVALIDATE,
         CONSTRAINT "T1_FK" FOREIGN KEY ("USER_ID")
          REFERENCES "OPS$TKYTE"."P" ("X") ENABLE NOVALIDATE
   ) PCTFREE 10 PCTUSED 40 INITRANS 1 MAXTRANS 255
  STORAGE(
  BUFFER_POOL DEFAULT)
  TABLESPACE "USERS"
  PARTITION BY HASH ("USER_ID")
 (PARTITION "SYS_P1017"
   TABLESPACE "USERS",
 PARTITION "SYS_P1018"
   TABLESPACE "USERS",
 PARTITION "SYS_P1019"
   TABLESPACE "USERS",
 PARTITION "SYS_P1020"
   TABLESPACE "USERS",
 PARTITION "SYS_P1021"
   TABLESPACE "USERS",
 PARTITION "SYS_P1022"
   TABLESPACE "USERS",
 PARTITION "SYS_P1023"
   TABLESPACE "USERS",
 PARTITION "SYS_P1024"
   TABLESPACE "USERS")



ops$tkyte%ORA10GR2> select constraint_name, constraint_type from user_constraints where 
table_name = 'T1';

CONSTRAINT_NAME                C
------------------------------ -
SYS_C0026838                   C
SYS_C0026839                   C
SYS_C0026840                   C
T1_PK                          P
T1_FK                          R

Reviews

May 20, 2008 - 1pm Central time zone