Assigning multiple fields in a loop using execute immediate - sql

Question

I am using PLPDF's libraries to create spreadsheets for various files - I am trying to get a procedure written to take the values of each field and one-by-one insert them into the spreadsheet. This operation can include many different tables going into many different spreadsheets, so just doing an export is not going to cut it.
This example is has two cursors created from tables - the USER_TAB_COLUMNS to select the column names, and the actual view query to pull the data. I have one loop to go through the data record by record, and second to go field-by-field within the record.
Before doing the actual writing to the spreadsheet blob, I'm simply running the dbms_output.putline to make sure that I am getting the data needed.
declare
q_str varchar2(100);
this_vc varchar2(3000);
cursor diet_table is
select * from vcars_diet where nhp_id = 8573;
cursor diet_stru is
select 'begin :1 := i.' || column_name || '; end;' line_o_code from user_tab_columns where table_name = 'VCARS_DIET';
begin
for i in diet_table loop
DBMS_OUTPUT.PUT_LINE ('--------------------------------------------------------');
for h in diet_stru loop
DBMS_OUTPUT.PUT_LINE ('Varchar Value for i: "' || h.line_o_code || '"');
EXECUTE IMMEDIATE (h.line_o_code) USING out this_vc;
DBMS_OUTPUT.PUT_LINE ('Varchar Value for i.' || h.line_o_code || ' is: '||this_vc);
end loop;
end loop;
end;
The fields in the diet table are:
NHP_ID
DATE_TIME
DIET_NO
FORM_NAME
DATA_TYPE
The results are:
ORA-06550: line 1, column 13:
PLS-00201: identifier 'I.NHP_ID' must be declared
ORA-06550: line 1, column 7:
PL/SQL: Statement ignored
ORA-06512: at line 33
06550. 00000 - "line %s, column %s:\n%s"
*Cause: Usually a PL/SQL compilation error.
*Action:

Answer 1

I have copied this PL/SQL code from Connor McDonald's solution from this AskTom article.
It uses type dynamic SQL to parse any SQL query and converts the column names as well as values into a collection. I've used a sample query on employees table in HR schema. Replace it with your query.
set serverout on size 999999
set verify off
declare
p_query varchar2(32767) :=
q'{select * from employees
where rownum = 1
}';-- Here you put your query
l_theCursor integer default dbms_sql.open_cursor;
l_columnValue varchar2(4000);
l_status integer;
l_descTbl dbms_sql.desc_tab;
l_colCnt number;
n number := 0;
procedure p(msg varchar2) is
l varchar2(4000) := msg;
begin
while length(l) > 0 loop
dbms_output.put_line(substr(l,1,80));
l := substr(l,81);
end loop;
end;
begin
execute immediate
'alter session set nls_date_format=''dd-mon-yyyy hh24:mi:ss'' ';
dbms_sql.parse( l_theCursor, p_query, dbms_sql.native );
dbms_sql.describe_columns( l_theCursor, l_colCnt, l_descTbl );
for i in 1 .. l_colCnt loop
dbms_sql.define_column(l_theCursor, i, l_columnValue, 4000);
end loop;
l_status := dbms_sql.execute(l_theCursor);
while ( dbms_sql.fetch_rows(l_theCursor) > 0 ) loop
for i in 1 .. l_colCnt loop
dbms_sql.column_value( l_theCursor, i, l_columnValue );
p( 'Value for '|| l_descTbl(i).col_name
|| ' is: ' ||
l_columnValue );
end loop;
dbms_output.put_line( '-----------------' );
n := n + 1;
end loop;
if n = 0 then
dbms_output.put_line( chr(10)||'No data found '||chr(10) );
end if;
end;
/
This gives the output:
Value for EMPLOYEE_ID is: 198
Value for FIRST_NAME is: Donald
Value for LAST_NAME is: OConnell
Value for EMAIL is: DOCONNEL
Value for PHONE_NUMBER is: 650.507.9833
Value for HIRE_DATE is: 21-jun-2007 00:00:00
Value for JOB_ID is: SH_CLERK
Value for SALARY is: 2600
Value for COMMISSION_PCT is:
Value for MANAGER_ID is: 124
Value for DEPARTMENT_ID is: 50
-----------------
PL/SQL procedure successfully completed.