What is the best way to copy data....

Question

Hello friends,
What could you think is the best way to copy this data ? :
- I have two identical databases (Oracle 9i)
- I want to migrate the data of 90 tables (all tables begin with the same string, i.e. 'TAB') from Database1 to database2.
- There are integrity constraints, referentials, etc.
I'd like to generate a script to automate/accelerate the process.
So, I'm thinking on the following:
- Disable all the constraints in Database2.
- Connect to Database 1 and generate a script with the 'inserts' using TOAD (or another similar application)
- In a Database 2 session, execute the script...
Of course if I use TOAD I can't generate an unique script to do this process in one step so...
Any better idea? (Using export/import, ... or some script you have...)
Thanks.
Jose.

Answer 1

Use exp and imp. It works... seriously! And you don't need to drop the user/schema. But don't take my word, run an example...
On Database 1
First let's create a couple of tables with referential integrity to each other to make sure exp/imp can handle it...
SQL> create table t1 (t1_id number constraint pk_t1 primary key, t2_id number);
Table created.
SQL> create table t2 (t2_id number constraint pk_t2 primary key, t1_id number);
Table created.
SQL> alter table t1 add constraint fk_t1_t2 foreign key (t2_id) references t2 (t2_id);
Table altered.
SQL> alter table t2 add constraint fk_t2_t1 foreign key (t1_id) references t1 (t1_id);
Table altered.
SQL> insert into t1 (t1_id, t2_id) values (1, null);
1 row created.
SQL> insert into t2 (t2_id, t1_id) values (2, 1);
1 row created.
SQL> update t1 set t2_id = 2 where t2_id is null;
1 row updated.
SQL> commit;
Commit complete.
SQL> select * from t1;
     T1_ID      T2_ID
         1          2
SQL> select * from t2;
     T2_ID      T1_ID
         2          1
SQL> select table_name, constraint_name, constraint_type, r_constraint_name from user_constraints
  2  where table_name in ('T1','T2');
TABLE_NAME                     CONSTRAINT_NAME                C R_CONSTRAINT_NAME
T1                             PK_T1                          P
T1                             FK_T1_T2                       R PK_T2
T2                             PK_T2                          P
T2                             FK_T2_T1                       R PK_T1
SQL>
Now let's export those tables. You can build a parfile manually or even spool it from a sql script with the names of all tables you need to export...
$ cat parfile.txt
tables=(\
t1,\
t2
$ exp rc/pwd parfile=parfile.txt file=db1.dmp log=db1.log
Export: Release 10.1.0.3.0 - Production on Mon Jan 9 20:49:17 2006
Copyright (c) 1982, 2004, Oracle.  All rights reserved.
Connected to: Oracle Database 10g Enterprise Edition Release 10.1.0.3.0 - Production
With the Partitioning, OLAP and Data Mining options
Export done in UTF8 character set and UTF8 NCHAR character set
About to export specified tables via Conventional Path ...
. . exporting table                             T1          1 rows exported
. . exporting table                             T2          1 rows exported
Export terminated successfully without warnings.
On Database 2
Copy your .dmp file to Database 2
Import
$ imp rc/pwd full=y file=db1.dmp log=db1_imp.log
Import: Release 10.1.0.3.0 - Production on Mon Jan 9 20:51:15 2006
Copyright (c) 1982, 2004, Oracle.  All rights reserved.
Connected to: Oracle Database 10g Enterprise Edition Release 10.1.0.3.0 - Production
With the Partitioning, OLAP and Data Mining options
Export file created by EXPORT:V10.01.00 via conventional path
import done in UTF8 character set and UTF8 NCHAR character set
. importing RC's objects into RC
. . importing table                           "T1"          1 rows imported
. . importing table                           "T2"          1 rows imported
About to enable constraints...
Import terminated successfully without warnings.
All data is there...
SQL> select * from t1;
     T1_ID      T2_ID
         1          2
SQL> select * from t2;
     T2_ID      T1_ID
         2          1 All constraints are there...
SQL> select table_name, constraint_name, constraint_type, r_constraint_name from user_constraints
  2  where table_name in ('T1','T2');
TABLE_NAME                     CONSTRAINT_NAME                C R_CONSTRAINT_NAME
T1                             PK_T1                          P
T1                             FK_T1_T2                       R PK_T2
T2                             PK_T2                          P
T2                             FK_T2_T1                       R PK_T1It does work!