Table compare and derive alter script between 2 schemas

Question

I am in Oracle 10g.
We are in need to synchronise table structures between two different database.
and execute the alter script in the target database.
I have an idea to find the tables which have the table definition changed using all_tab_columns and datbase link;
A sample of it as below:
prompt
prompt columns having same name but difference in datatype or length:
prompt -------------------------------------------------------------------------
select
a.column_name, a.data_type, a.data_length, a.data_scale,a.data_precision,
b.column_name, b.data_type, b.data_length, b.data_scale,b.data_precision
from
all_tab_columns a, all_tab_columns@link b
where
a.table_name in (select tablename from test) and
a.table_name = b.table_name and
a.column_name = b.column_name and
a.data_type <> b.data_type or
a.data_length <> b.data_length or
a.data_scale <> b.data_scale or
a.data_precision <> b.data_precision
prompt columns present in &table1 but not in &table2
prompt ----------------------------------------------
select
column_name
from
all_tab_columns@link
where
table_name in (select tablename from test)
minus
select
column_name --, data_type, data_length, data_scale, data_precision
from
all_tab_columns
where
table_name in (select tablename from test) ;
prompt columns present in &table2 but not in &table1
prompt ----------------------------------------------
select
column_name --, data_type, data_length, data_scale, data_precision
from
all_tab_columns@link
where
table_name in (select tablename from test)
minus
select
column_name
from
all_tab_columns
where
table_name in (select tablename from test)
just looking for idea to derive the alter scripts on these? Please share your ideas on this.

Answer 1

You don't have to write lots of triggers. You only need to write one trigger e.g :-
create table ddl_audit
(audit_date date,
username varchar2(30),
instance_number integer,
database_name varchar2(9),
object_type varchar2(19),
object_owner varchar2(30),
object_name varchar2(128),
sql_text varchar2(2000));
create or replace trigger BEFORE_DDL_TRG before ddl on database
declare
l_sql_text ora_name_list_t;
l_count NUMBER;
l_puser VARCHAR2(30) := NULL;
l_sql varchar2(2000);
begin
l_count := ora_sql_txt(l_sql_text);
l_puser := SYS_CONTEXT('USERENV', 'KZVDVCU');
l_count := ora_sql_txt(l_sql_text);
for i in 1..l_count
loop
l_sql := l_sql||l_sql_text(i);
end loop;
insert into ddl_audit (audit_date, username, instance_number, database_name, object_type, object_owner, object_name, sql_text)
values (sysdate, l_puser,ora_instance_num,ora_database_name,ora_dict_obj_type,ora_dict_obj_owner,ora_dict_obj_name,l_sql);
exception
when others then
null;
end;
show errors;