Code generation example

Question

Hi again,
Does somebody have a small example for of some plsql code that actually generates plsql code?
I' trying something like below but it does not seem to work ...
TIA,
Stefan
CREATE OR REPLACE PROCEDURE TstCodeGen(tbl_name IN VARCHAR2)
IS
sqltext varchar2(10240);
BEGIN
DBMS_OUTPUT.PUT_LINE('Start');
sqltext := 'CREATE OR REPLACE PROCEDURE testGenerated IS' || chr(10);
sqltext := sqltext || 'TYPE tbl_name_TYPE IS REF CURSOR;' || chr(10);
sqltext := sqltext || 'tbl_names_cu tbl_name_TYPE;' || chr(10);
sqltext := sqltext || 'num_records INTEGER;' || chr(10);
sqltext := sqltext || 'mytabnames ' || tbl_name || '%ROWTYPE;' || chr(10);
sqltext := sqltext || 'sql_select_table_names varchar2(200);' || chr(10);
sqltext := sqltext || 'sqltxt varchar2(200);' || chr(10);
sqltext := sqltext || 'BEGIN' || chr(10);
sqltext := sqltext || ' sql_select_table_names:=''SELECT * FROM '||tbl_name||''';' || chr(10);
sqltext := sqltext || ' execute immediate sql_select_table_names;' || chr(10);
sqltext := sqltext || 'END;' || chr(10);
sqltext := sqltext || '/' || chr(10);
DBMS_OUTPUT.PUT_LINE(sqltext);
execute immediate sqltext;
DBMS_OUTPUT.PUT_LINE('sqltext executed??');
sqltext := 'exec testGenerated;';
execute immediate sqltext;
DBMS_OUTPUT.PUT_LINE('Done');
END;
show errors;

Answer 1

I would say extremly weird and definitely of no real practical use ... but at least doable, when the correct syntax is applied:
SQL> CREATE OR REPLACE PROCEDURE tstcodegen (tbl_name IN VARCHAR2)
  2  IS
  3     sqltext   VARCHAR2 (10240);
  4  BEGIN
  5     DBMS_OUTPUT.put_line ('Start');
  6     sqltext := 'CREATE OR REPLACE PROCEDURE testGenerated IS' || CHR (10);
  7     sqltext := sqltext || 'TYPE tbl_name_TYPE IS REF CURSOR;' || CHR (10);
  8     sqltext := sqltext || 'tbl_names_cu tbl_name_TYPE;' || CHR (10);
  9     sqltext := sqltext || 'num_records INTEGER;' || CHR (10);
10     sqltext := sqltext || 'mytabnames ' || tbl_name || '%ROWTYPE;' || CHR (1
0);
11     sqltext := sqltext || 'sql_select_table_names varchar2(200);' || CHR (10
12     sqltext := sqltext || 'sqltxt varchar2(200);' || CHR (10);
13     sqltext := sqltext || 'BEGIN' || CHR (10);
14     sqltext :=
15        sqltext || ' sql_select_table_names:=''SELECT * FROM ' || tbl_name
16        || ''';' || CHR (10);
17     sqltext :=
18            sqltext || ' execute immediate sql_select_table_names;' || CHR (1
0);
19     sqltext := sqltext || 'END;';
20  -- sqltext := sqltext || '/' || CHR (10);
21     DBMS_OUTPUT.put_line (sqltext);
22
23     EXECUTE IMMEDIATE sqltext;
24
25     DBMS_OUTPUT.put_line ('sqltext executed??');
26     sqltext := 'begin testGenerated; end;';
27
28     EXECUTE IMMEDIATE sqltext;
29
30     DBMS_OUTPUT.put_line ('Done');
31  END tstcodegen;
32  /
Prozedur wurde erstellt.
SQL>
SQL> SHOW errors;
Keine Fehler.
SQL>
SQL> EXEC tstcodegen('emp')
Start
CREATE OR REPLACE PROCEDURE testGenerated IS
TYPE tbl_name_TYPE IS REF
CURSOR;
tbl_names_cu tbl_name_TYPE;
num_records INTEGER;
mytabnames
emp%ROWTYPE;
sql_select_table_names varchar2(200);
sqltxt varchar2(200);
BEGIN
sql_select_table_names:='SELECT * FROM emp';
execute immediate
sql_select_table_names;
END;
sqltext executed??
Done
PL/SQL-Prozedur erfolgreich abgeschlossen.