Create table dynamically

Question

I need help creating a table dynamically. i have a view in one database. i would like to create a table in another instance using the view structure of a view which is in another instance. the problem i am having is that some columns in the view are always null so they appear as a varchar2 datatype without lenght.
when i do an insert/select it does not create the table because of this problem. so i would like to know if anybody know how to create a script to handle this case and create my table dynamically.
there was a script in the code tips section in oracle site but i lost that script. please provide code on how to do this. thanks

Answer 1

Hi,
SQL> create or replace view v as
  2    select null a, to_number(null) as b, to_date(null) as c,
  3      to_nchar(null) as d,
  4      11 as e, 1.11 as f,
  5      'fff' as g, to_nchar('cvfgfg') as h, sysdate as i
  6    from dual;
View created.
SQL> DECLARE
  2    vCreate_Sql VARCHAR2(32000);
  3    vFirst_Col BOOLEAN;
  4  BEGIN
  5    vCreate_Sql := 'CREATE TABLE T (';
  6    vFirst_Col := TRUE;
  7    FOR cRec IN (
  8      SELECT Column_Name, Data_Type, Data_Precision, Data_Scale, Char_Col_Decl_Length
  9      FROM User_Tab_Columns
10      WHERE Table_Name = 'V'
11    ) LOOP
12      IF vFirst_Col THEN
13        vFirst_Col := FALSE;
14      ELSE
15        vCreate_Sql := vCreate_Sql || ',';
16      END IF;
17 
18      vCreate_Sql := vCreate_Sql || cRec.Column_Name || ' ' || cRec.Data_Type ||
19        CASE
20          WHEN cRec.Data_Type IN ('CHAR', 'VARCHAR2', 'NCHAR', 'NVARCHAR2') THEN
21            '(' || TO_CHAR(GREATEST(1, cRec.Char_Col_Decl_Length)) || ')'
22          WHEN cRec.Data_Type = 'NUMBER' THEN
23            CASE
24              WHEN cRec.Data_Precision IS NULL THEN ''
25              WHEN cRec.Data_Precision IS NOT NULL AND cRec.Data_Scale IS NULL THEN
26                '(' || TO_CHAR(cRec.Data_Precision) || ')'
27              WHEN cRec.Data_Precision IS NOT NULL AND cRec.Data_Scale IS NOT NULL THEN
28                '(' || TO_CHAR(cRec.Data_Precision) || ', ' || TO_CHAR(cRec.Data_Scale) || ')'
29            END
30            /* ... Possibly other datatypes */
31          ELSE
32            ''
33        END;
34    END LOOP;
35    vCreate_Sql := vCreate_Sql || ')';
36 
37    EXECUTE IMMEDIATE vCreate_Sql;
38  END;
39  /
PL/SQL procedure successfully completed.
SQL> desc v
Name                                      Null?    Type
A                                                  VARCHAR2
B                                                  NUMBER
C                                                  DATE
D                                                  VARCHAR2
E                                                  NUMBER
F                                                  NUMBER
G                                                  CHAR(3)
H                                                  NVARCHAR2(6)
I                                                  DATE
SQL> desc t
Name                                      Null?    Type
A                                                  VARCHAR2(1)
B                                                  NUMBER
C                                                  DATE
D                                                  VARCHAR2(1)
E                                                  NUMBER
F                                                  NUMBER
G                                                  CHAR(3)
H                                                  NVARCHAR2(6)
I                                                  DATERegards,
Dima