Select * from emp where ename=(procedure1(procedure2(procedure3)));

Question

I have a big problem
I have to check the data for quality data
Lets say i have to check data in emp table
First i have to check whether the empno is of type number
     IF empno=number then
          if ename starts with a particualar format then
               ---printouts and this procedure goes on for about 10 coulumns
I have designed a hard coded procedure where I input table name and column name and the procedure does the checks and give out result
I have planned to call that procedures here for each checks
its like i make the procedure to execute and the procedure returns rowid of the correct data
now i have to apply the second procedure where input is all the rowids of previous procedure and it goes on
I even dont know whether procedure is correct or function is correct
Its like select * from emp where ename=(procedure1(procedure2(procedure3)));
each procedure's output is Rowids only which satisfy a particular format of data
Please explain me in details
Please please help me.

Answer 1

Nested calls are not the best of ideas. Ignoring that for a moment, there are a couple of ways to address this requirement in Oracle. One of these, and likely one of the more scalable ways, is to use Pipeline Table Functions.
The following code demonstrates the basics of this approach, using pipelined table functions to perform validation checks on data.
SQL> -- generic type to serve as input cursors to the validation functions
SQL> create or replace type TFormatCheckRow as object
  2  (
  3          row_identifier  varchar2(30),
  4          value           varchar2(100)
  5  );
  6  /
Type created.
SQL>
SQL> -- validation functions returns the rowid of rows that are valid
SQL> create or replace type TRowID as object
  2  (
  3          row_identifier  varchar2(30)
  4  );
  5  /
Type created.
SQL>
SQL> create or replace type TRowIDTable is table of TRowID;
  2  /
Type created.
SQL>
SQL>
SQL> create or replace package LIB is
  2
  3          type    TCursor is REF CURSOR;
  4  end;
  5  /
Package created.
SQL>
SQL> -- sample validation function to check if the value is a valid NUMBER, and
SQL> -- if so will return the rowid of that row for further processing
SQL> create or replace function ValidateNumber( c LIB.TCursor ) return TRowIDTable
  2          pipelined is
  3
  4          MAX_FETCH_SIZE  constant number := 100;
  5          type    TBuffer is table of TFormatCheckRow;
  6
  7          buffer  TBuffer;
  8
  9          function IsNumber( val varchar2 ) return boolean is
10                  n       number;
11          begin
12                  n := TO_NUMBER( val );
13                  return( TRUE );
14          exception when OTHERS then
15                  return( FALSE );
16          end;
17
18  begin
19          loop
20                  fetch c bulk collect into buffer limit MAX_FETCH_SIZE;
21
22                  for i in 1..buffer.Count
23                  loop
24                          if IsNumber( buffer(i).value ) then
25                                  PIPE ROW( TRowID( buffer(i).row_identifier ) );
26                          end if;
27                  end loop;
28
29                  exit when c%NOTFOUND;
30          end loop;
31
32          close c;
33
34          return;
35  end;
36  /
Function created.
SQL> show error
No errors.
SQL>
SQL>
SQL> -- a sample table to check
SQL> create table foo_tab
  2  (
  3          some_value      varchar2(20)
  4  )
  5  /
Table created.
SQL>
SQL>
SQL> -- put some data into the table
SQL> insert
  2  into       foo_tab
  3  select
  4          object_id
  5  from       all_objects
  6  where      rownum < 11
  7  /
10 rows created.
SQL>
SQL> insert
  2  into       foo_tab
  3  select
  4          SUBSTR(object_name,1,20)
  5  from       all_objects
  6  where      rownum < 11
  7  /
10 rows created.
SQL>
SQL> commit;
Commit complete.
SQL>
SQL> -- return rowids of all rows from FOO_TAB where the column SOME_VALUE is a valid number
SQL> select
  2          row_identifier
  3  from       TABLE(ValidateNumber( CURSOR(select TFormatCheckRow(f.rowid,f.some_value) from foo_tab f) ))
  4  /
ROW_IDENTIFIER
AAAOQKAAEAAAAFQAAA
AAAOQKAAEAAAAFQAAB
AAAOQKAAEAAAAFQAAC
AAAOQKAAEAAAAFQAAD
AAAOQKAAEAAAAFQAAE
AAAOQKAAEAAAAFQAAF
AAAOQKAAEAAAAFQAAG
AAAOQKAAEAAAAFQAAH
AAAOQKAAEAAAAFQAAI
AAAOQKAAEAAAAFQAAJ
10 rows selected.
SQL>
SQL>
SQL> -- list the rows that contain valid numbers
SQL> with ROWID_LIST as
  2  (
  3  select
  4          row_identifier
  5  from       TABLE(ValidateNumber( CURSOR(select TFormatCheckRow(f.rowid,f.some_value) from foo_tab f) ))
  6  )
  7  select
  8          *
  9  from       foo_tab f
10  where      f.rowid in (select row_identifier from ROWID_LIST)
11  order by 1
12  /
SOME_VALUE
258
259
311
313
314
316
317
319
605
886
10 rows selected.
SQL>