Oracle APEX: Execute immediate on collection - plsql

I have the following code:
declare
y pls_integer := 0;
v_msg varchar2(4000);
plsql varchar(4000);
begin
if not apex_collection.collection_exists(p_collection_name=>'P16_COLLECTION') then
wwv_flow.debug('No Apex collection found!');
else
for x in (select * from apex_collections where collection_name = 'P16_COLLECTION' and seq_id > 1 order by seq_id)
loop
y := y+1;
FOR i IN 1..25
LOOP
plsql := 'begin apex_collection.update_member_attribute (p_collection_name=> ''P16_COLLECTION'', p_seq=>' || TO_CHAR(x.seq_id) || ',p_attr_number =>' || TO_CHAR(i) || ',p_attr_value=>wwv_flow.g_f' || TO_CHAR(i, 'FM00') || '(' || TO_CHAR(y) || ')); end;';
wwv_flow.debug(plsql);
EXECUTE IMMEDIATE plsql;
END LOOP;
end loop;
end if;
exception when others then
v_msg := ''||sqlerrm;
wwv_flow.debug('ERR: '||v_msg);
end;
This code is very similar to the one proposed here, but I loop through 25 columns. The issue with Oracle Apex is the max number of chars PL/SQL is allowed to have, so I am unable to just write 25 update_member_attribute - calls.
But instead of a it excecuting I get an error no data found.
I triple checked that the collection P16_COLLECTION exists.

The issue with Oracle Apex is the max number of chars PL/SQL is allowed to have
I'm not sure I understood this statement. It is PL/SQL you use. You declared a local PLSQL variable as VARCHAR2(4000). Why didn't you specify its max allowed size, 32767? Would that help?
Furthermore, saying that you got NO-DATA-FOUND exception: are you sure that this piece of code raised it? Because, there's no SELECT statement in there ... the one you used in a cursor FOR loop can't raise NO-DATA-FOUND; UPDATE either. Therefore, it must be something else, I presume.
Enable DEBUG, run the page and - when you get the error - view debug results and locate the culprit.

Related

PL/SQL if then else statements not running

I have written following code in oracle pl/sql
create or replace procedure sorting_criteria(criteria in varchar)
as
begin
if(criteria='lowest price')
then
declare
p_name product.p_name%type;
cursor ptr is select p_name from product order by amount ASC;
begin
open ptr;
loop
fetch ptr into p_name;
exit when ptr%notfound;
dbms_output.put_line(p_name);
end loop;
close ptr;
end;
else if(criteria='highest price')
then
declare
p_name product.p_name%type;
cursor ptr is select p_name from product order by amount DESC;
begin
open ptr;
loop
fetch ptr into p_name;
exit when ptr%notfound;
dbms_output.put_line(p_name);
end loop;
close ptr;
end;
else
dbms_output.put_line('Enter valid criteria!');
end if;
end;
/
But it is giving following error: Error at line 35: PLS-00103: Encountered the symbol ";" when expecting one of the following: Please help
The ELSE-IF statement in PL/SQL has to be written as ELSIF. Otherwise, you should close the second IF with an other END IF; statement.
You can solve the issue by changing the ELSE IF at line 17 to an ELSIF
The answer by #GregorioPalamà correctly addresses your issues. But you can drastically reduce the workload by changing your thinking away from "If...then...else" to the "set of" and letting SQL do the work. In this case the only difference is sorting either ascending or descending on amount. The same effect can be achieved by sorting ascending on amount or minus amount; and SQL can make that decision. So you can reduce the procedure to validating the parameter and a single cursor for loop:
create or replace procedure sorting_criteria(criteria in varchar2)
as
cursor ptr(c_sort_criteria varchar2) is
select p_name
from product
order by case when c_sort_criteria = 'lowest price'
then amount
else -amount
end ;
begin
if criteria in ('lowest price', 'highest price')
then
for rec in ptr(criteria)
loop
dbms_output.put_line('Product: ' || rec.p_name );
end loop;
else
dbms_output.put_line('Enter valid criteria!');
end if;
end sorting_criteria;
/
See demo here. For demonstration purposed I added the amount to the dbms_output.
A couple notes:
While it is not incorrect using p_... as a column name, it is also
not a good idea. A very common convention (perhaps almost a
standard) to use p_... to indicate parameters. This easily leads to
confusion; confusion amongst developers is a bad thing.
IMHO it is a bug to name a local variable the same as a table
column name. While the compiler has scoping rules which one to use
it again leads to confusion. The statement "where table.name = name"
is always true, except when at least one of them is null, which possible could lead to updating/deleting every row in your table. In this
case p_name is both a column and a local variable.

Unable to get user input in PL in sqldeveloper

I'm trying to get user input in SQLDeveloper in a procedure. But however , I'm getting some error like "missing defines". Please help me to solve this. Thanks in advance.
DECLARE
a NUMBER(5);
BEGIN
a := :a;
DBMS_OUTPUT.PUT_LINE('We took the number as ' || a);
END;
The error looks like this.
Error starting at line : 1 in command -
DECLARE
a NUMBER(5);
BEGIN
a := :a;
DBMS_OUTPUT.PUT_LINE('We took the number as ' || a);
END;
Error report -
Missing defines
We took the number as 15
Although I'm getting the correct answer at bottom, still why this errors?
Please execute the below statement:
DECLARE
a NUMBER(5):=15;
BEGIN
a := a;
DBMS_OUTPUT.PUT_LINE('We took the number as ' || a);
END;
In order to get user input in PLSQL Block, we use &, &givenumber will get the user input at run time.
DECLARE
a NUMBER(5);
BEGIN
a := &givenumber;
DBMS_OUTPUT.PUT_LINE('We took the number as ' || a);
END;

Can anyone help whey my execption section is not working,

My whole intention to catch exception,WRONG parameter is NOT CATCHING exception.
Here is the code:
CREATE OR REPLACE PROCEDURE list_emp (p_emp_id IN employees.employee_id%TYPE,
p_dept_id IN employees.department_id%TYPE)
IS
CURSOR c1 IS
SELECT *
FROM EMPLOYEES
WHERE EMPLOYEE_ID=p_emp_id
AND DEPARTMENT_ID=p_dept_id;
emp_rec c1%ROWTYPE;
BEGIN
OPEN c1;
LOOP
FETCH c1 INTO emp_rec;
EXIT WHEN c1%NOTFOUND;
DBMS_OUTPUT.PUT_LINE(emp_rec.employee_id||' '||emp_rec.first_name||' '||emp_rec.last_name);
END LOOP;
CLOSE c1;
EXCEPTION
WHEN NO_DATA_FOUND THEN
DBMS_OUTPUT.PUT_LINE('No Record Found ');
WHEN OTHERS THEN
DBMS_OUTPUT.PUT_LINE('No Record Found ');
END;
When the cursor is opened and fetched with the wrong parameter that does not match any row from the corresponding table, the following line
EXIT WHEN c1%NOTFOUND;
cause the plsql procedure to terminate (because there were no rows found). Hence no exception is raised.
If you do want to display some sort of output you can do the following instead
IF c1%FOUND THEN
dbms_output.put_line('Record Found');
ELSE
dbms_output.put_line('Finished/Done');
EXIT;
END IF;
If you want to raise an error after looping through a cursor that returns no rows, then you're going to have to use a counter to work out how many rows have been processed, and then you can do something if no rows have been processed.
Something like:
create or replace procedure list_emp (p_emp_id in employees.employee_id%type,
p_dept_id in employees.department_id%type)
is
cursor c1 is
select employee_id,
first_name,
last_name
from employees
where employee_id = p_emp_id
and department_id = p_dept_id;
v_count number := 0;
begin
for emp_rec in c1
loop
v_count := v_count + 1;
dbms_output.put_line(emp_rec.employee_id||' '||emp_rec.first_name||' '||emp_rec.last_name);
end loop;
if v_count = 0 then
raise no_data_found;
end if;
exception
when no_data_found then
dbms_output.put_line('No Record Found.');
raise;
when others then
dbms_output.put_line('An error occurred: '||sqlerrm);
raise;
end;
/
A few notes:
I converted your cursor loop into a cursor-for-loop; you don't need to worry about declaring the record type and also Oracle handles the opening and closing of the cursor for you.
I added raise; to each of your exception handlers - in general, having when others then null (which is effectively what your original code was doing - no errors are raised to the calling code) is a bad idea. I added the raise to the no_data_found condition as that wasn't doing anything either; typically, if you have an exception condition, you want it to do something to let the calling code know there was a problem (not always, of course; sometimes you don't want the processing to stop if a particular error condition is met).
Your cursor was selecting all columns, but in your procedure, you were only using three of them. I've therefore amended the cursor so that it only pulls back those three columns.
Don't rely on dbms_output in your production code. Code that calls this procedure won't see anything populated in dbms_output, unless it explicitly looks for it - and that's not something I've ever seen in any production code, outside of Database tools (eg. SQL*Plus, Toad, etc). I've left this in your procedure as I've a feeling this is a learning exercise for you, but please don't think that this is in any way acceptable in production code.
You're passing p_emp_id in as a parameter - typically, that's the primary key of the employees table. If that's the case, then there's no need for the cursor for loop at all - you could do it by using select ... into ... instead, like so:
.
create or replace procedure list_emp (p_emp_id in employees.employee_id%type,
p_dept_id in employees.department_id%type)
is
v_emp_id employees.employee_id%type;
v_first_name employees.first_name%type;
v_last_name employees.last_name%type;
begin
select employee_id,
first_name,
last_name
into v_emp_id,
v_first_name,
v_last_name
from employees
where employee_id = p_emp_id
and department_id = p_dept_id;
dbms_output.put_line(emp_rec.employee_id||' '||emp_rec.first_name||' '||emp_rec.last_name);
exception
when no_data_found then
dbms_output.put_line('No Record Found.');
raise;
when others then
dbms_output.put_line('An error occurred: '||sqlerrm);
raise;
end;
/
Alternatively, just pass back a ref cursor:
create or replace procedure list_emp (p_emp_id in employees.employee_id%type,
p_dept_id in employees.department_id%type,
p_ref_cur out sys_refcursor)
is
begin
open p_ref_cur for select employee_id,
first_name,
last_name
from employees
where employee_id = p_emp_id
and department_id = p_dept_id;
-- No need for an exception handler here since you're not storing the error details anyway.
-- By not having an error handler, any error will automatically be raised up to the calling code
-- and it will have the correct error stack trace info (e.g. the line number the error occurred,
-- rather than the line the error was reraised from
end;
/
And to run the ref cursor in SQL*Plus (or as a script in Toad/SQL Developer/etc), you do the following:
-- create a variable outside of PL/SQL to hold the ref cursor pointer (this is a SQL*Plus command):
variable rc refcursor;
-- populate our ref cursor variable with the pointer. Note how we pass it in as a bind variable
begin
list_emp(p_emp_id => 1234,
p_dept_id => 10,
p_ref_cur => :rc);
end;
/
-- finally, print the contents of the ref cursor.
print rc;

Oracle PL/SQL - ORA-01403 “No data found” when using “SELECT INTO”

I have a pl sql code that execute three queries sequentially to determine a match level and do some logic
The issue is - when first query has no results (completely valid scenario) I get ORA-01403 No data found.
I understand that I need to incorporate [ Exception clause when NO_DATA_FOUND ]- but how to add it and continue to the next query?
PL/SQL Code
SELECT A into PARAM A FROM SAMPLE WHERE SOME CONDITION;
-- GOT ORA-01403 No data found HERE
MATCH_LEVEL =1;
if A is null then
do some logic;
end if
SELECT A INTO PARAM_B FROM SAMPLE WHERE SOME OTHER CONDITION
MATCH_LEVEL =2
if A is null then
do some logic 2;
end if
SELECT A INTO PARAM_B FROM SAMPLE WHERE SOME OTHER CONDITION
MATCH_LEVEL =3
if A is null then
do some logic 3;
end if
END PL/SQL Code
Declare
--your declarations
begin
SELECT A into PARAM A FROM SAMPLE WHERE SOME CONDITION;
-- GOT ORA-01403 No data found HERE
Begin
MATCH_LEVEL =1;
if A is null then
do some logic;
end if;
EXCEPTION
WHEN NO_DATA_FOUND THEN
dbms_output.put_line ('Error...');
END;
--- and son on for other blocks
end;
Just surround your SELECT INTO with begin-end;
begin
-- your faulty statement here
Exception
When NO_DATA_FOUND Then
-- Do what you want or nothing
WHEN TOO_MANY_ROWS THEN
-- what if you get more then one row? and need specific handler for this
When OTHERS Then
-- do something here or nothing (optional - may happen if you have more than your SELECT INTO between 'begin' and 'Exception')
end;
This is like try block of PL/Sql
With this technique you can log the reason your statement failed.
For a SELECT ... INTO ... statement, the PL/SQL engine assume there will be one, and only one row returned by your query. If there is no row, or more than one, an exception is raised.
FWIW, you can handle such cases without resorting on exception handling by using aggregate functions. That way, there will always be only one row in the result set.
Assuming A can't be NULL in your rows:
SELECT MAX(A) into PARAM A FROM SAMPLE WHERE SOME CONDITION;
-- A would be NULL if there was *no* row. Otherwise, it is *the* value for *the* row
MATCH_LEVEL =1;
if A is null then
do some logic;
end if
If the NULL value is a possible case, just add an extra COUNT(*) column:
SELECT MAX(A), COUNT(*) into A, HAS_FOUND_ROW FROM SAMPLE WHERE SOME CONDITION;
if HAS_FOUND_ROW > 0 then
...
end if;
Oracle will not allow you to open an implicit cursor (i.e. a select statement in the body of a code block) that returns no rows. You have two options here (3 really, counting #Sylvain's answer, but that is an unusual approach): use an explicit cursor or handle the error.
Explicit Cursor
An explicit cursor is one found in the DECLARE section it must be opened and fetched manually (or in a FOR loop). This has the added advantage that, if you parameterize the query properly, you can write it once and use it multiple times.
DECLARE
a sample.a%type;
MATCH_LEVEL number;
cursor cur_params (some_column_value number) is
SELECT A FROM SAMPLE WHERE some_column = some_column_value;
BEGIN
MATCH_LEVEL := 1;
open cur_params (match_level);
fetch cur_params into a;
close cur_params;
if A is null then
null; --some logic goes here
end if;
MATCH_LEVEL := 2;
open cur_params (match_level);
fetch cur_params into a;
close cur_params;
if A is null then
null; --some logic goes here
end if;
end;
Handle the error
If you choose to handle the error, you'll need to create a BEGIN...END block around the code that is going to throw the error. When disregarding an error, it's crucial that you ensure that you are only disregarding the specific error you want avoid, when generated from the specific statement you expect it from. If you simply add the EXCEPTION section to your existing BEGIN...END block, for instance, you couldn't know which statement generated it, or even if it was really the error you expected.
DECLARE
a sample.a%type;
MATCH_LEVEL number;
BEGIN
MATCH_LEVEL := 1;
BEGIN
SELECT A into A FROM SAMPLE WHERE some_column = MATCH_LEVEL;
EXCEPTION
WHEN NO_DATA_FOUND THEN
null; --Do nothing
END;
if A is null then
null; --some logic goes here
end if;
MATCH_LEVEL := 2;
BEGIN
SELECT A into A FROM SAMPLE WHERE some_column = MATCH_LEVEL;
EXCEPTION
WHEN NO_DATA_FOUND THEN
null; --Do nothing
END;
if A is null then
null; --some logic goes here
end if;
end;
While I'd discourage it, you can catch any other errors in the same exception blocks. However, by definition, those errors would be unexpected, so it would be a poor practice to discard them (you'll never know they even happened!). Generally speaking, if you use a WHEN OTHERS clause in your exception handling, that clause should always conclude with RAISE;, so that the error gets passed up to the next level and is not lost.

Assign value to a field of rowtype where `field name` is a string

I want to assign a value to a rowtype's field but I don't know how to do it.
Suppose that I have a table X inside my database.
Suppose also that I have the following variables
a ( X%ROWTYPE ), representing a row of the table X
b ( VARCHAR2 ), containing a column name of the table X
c ( VARCHAR2 ), containing what I want to store inside a.b
What I want to do : something like a.b := c.
I've come up with something like this :
EXECUTE IMMEDIATE 'SELECT '|| c || ' INTO a.' || b || ' FROM DUAL';
Apparently, this isn't the right way to go. I get a ORA-0095: missing keyword error.
Can anyone help me with this ?
Here is the complete code :
DECLARE
tRow MyTable%ROWTYPE;
col_name VARCHAR(10) := 'Length';
nValue NUMBER(12,4) := 0.001;
dynamic_request VARCHAR(300);
BEGIN
dynamic_request := 'SELECT '|| nValue || ' INTO tRow.' || col_name || ' FROM DUAL';
EXECUTE IMMEDIATE dynamic_request;
END;
Ok, I solved it !
Short answer : Using a global variable does the trick
Answer Development
Let us consider two facts about dynamic PL/SQL blocks (i.e., PL/SQL blocks written as strings, to be executed trough an EXECUTE IMMEDIATE statement)
[1] There is no such thing as variable scope when you create a dynamic PLSQL block. What I mean by that is, if you do something like this :
CREATE OR REPLACE PROCEDURE DynamicVariableAssignment(
theString IN VARCHAR2
)
IS
BEGIN
EXECUTE IMMEDIATE 'BEGIN theString := ''test''; END; ';
END;
it will simply not work because the scope of theString is not transfered to the dynamic PL/SQL block. In other words, the dynamic PL/SQL block doesn't "inherit" of any variable, wherever it is executed.
[2] You might say "OK, no panic, I can give input/output arguments to my dynamic PL/SQL block, right ?". Sure you can, but guess what : you can only give SQL types as in/out ! True PL/SQL types on the other hand, such as a myTable%rowtype, are not accepted as an input for a dynamic PL/SQL block. So the answer of hmmftg won't work either :
-- I've reduced the code to the interesting part
dynamic_request := 'BEGIN :t_row.' || col_name || ':= 0.001; END;';
EXECUTE IMMEDIATE dynamic_request USING IN OUT tRow;
-- (where tRow is of type myTable%ROWTYPE)
since tRow is of MyTable%ROWTYPE, it is not a valid SQL type and is therefore not valid as an input to the dynamic PL/SQL block.
The Solution Who would have thought that global variables would come and save the day ? As we said in [1], we have no reference to any variable outside the dynamic PL/SQL block. BUT we can still access global variables defined in package headers !
Let us assume that I have a package kingPackage in which I define the following :
tempVariable myTable%ROWTYPE;
Then I can do this :
FINAL CODE (body only)
-- Copy tRow into temp variable
kingPackage.tempVariable := tRow;
-- We modify the column of the temp variable
vString := 'BEGIN kingPackage.tempVariable.' || col_val || ' := ' || TO_CHAR(vNumber) ||'; END;';
EXECUTE IMMEDIATE vString;
-- The column value has been updated \o/
tRow := kingPackage.tempVariable;
There you go, fellas !
Have a nice day
try this:
CREATE OR REPLACE PROCEDURE ROW_CHANGER(
tRow IN MyTable%ROWTYPE,
col_name IN VARCHAR,
nValue IN NUMBER)
AS
dynamic_request VARCHAR(300);
BEGIN
dynamic_request := 'BEGIN :t_row.'||COL_NAME ||':= :n_value; END;';
EXECUTE IMMEDIATE dynamic_request
USING IN OUT TROW, IN nValue;
END;
this is because in your EXECUTE IMMEDIATE the tRow MyTable%ROWTYPE is not defined,
so we defined it with using statement.

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