Create view with dynamic from-clause

Question

Dear all,
you might have some ideas to help me out of my issue that i just "created myself" ;-)
i have a unknown and non-constant amount of tables using the the same table-structure and i do have a master table
that contains all names of these kind of tables. I now want to create a single view that contains all columns of each table
and an additional column name containing the name of the corresponding table.
I found a solution for this but only if I knew all table names while creating my view.
Here's what I currently have:
master_table:
ID TABLENAME
1 table_01
2 table_02
table_01:
ID NAME
1 eins
2 zwei
3 drei
table_02:
ID NAME
1 one
2 two
3 three
my view "tab1tab2" on these 2 table looks like this:
ID NAME TABLENAME
1 eins table_01
2 zwei table_01
3 drei table_01
1 one table_02
2 two table_02
3 three table_02
i achieved this view by using:
CREATE OR REPLACE VIEW TAB1TAB2 ("ID", "NAME", "TABLENAME")
AS
SELECT id,name, 'table_01' AS tablename FROM table_01
UNION
SELECT id,name, 'table_02' AS tablename FROM table_02;
Is there a way to create as many select and union statements as i do have entries (tablenames) in my master_table to achive the same results as my hardcoded view ?
Many thanks in advance for your help
Best regards
majo

Answer 1

Is there a way to create as many select and union statements as i do have entries (tablenames) in my master_table to achive the same results as my hardcoded view ?You can achieve this also with some xml facilities as e.g. in
SQL> create table t1 as select empno, ename from emp where rownum <= 3
Table created.
SQL> create table t2 as select deptno empno, dname ename from dept
Table created.
SQL> create table master as (select 1 id, 't1' table_name from dual union all
                                   select 2 id, 't2' table_name from dual)
Table created.
SQL> create or replace view v_t
as
select table_name, x.*
  from (select table_name, 'ora:view("' || table_name || '")' tabs from master),
       xmltable (tabs columns id int path 'EMPNO', ename varchar2(20) path 'ENAME') x
View created.
SQL> select * from v_t
TABLE_NAME              ID ENAME              
t1                    7369 SMITH              
t1                    7499 ALLEN              
t1                    7521 WARD               
t2                      10 ACCOUNTING         
t2                      20 RESEARCH           
t2                      30 SALES              
t2                      40 OPERATIONS         
t2                      50 SALES              
8 rows selected.
SQL> create table t3 as select object_id empno, object_name ename from user_objects where rownum <= 3
Table created.
SQL> insert into master values (3, 't3')
1 row created.
SQL> select * from v_t
TABLE_NAME              ID ENAME              
t1                    7369 SMITH              
t1                    7499 ALLEN              
t1                    7521 WARD               
t2                      10 ACCOUNTING         
t2                      20 RESEARCH           
t2                      30 SALES              
t2                      40 OPERATIONS         
t2                      50 SALES              
t3                  187449 ABC                
t3                  187448 ADDRESSES_EXT_TAB  
t3                  187446 ADDRESSES_EXT_TYP  
11 rows selected.Note: above will work only in 11g.