How to wrap an Oracle stored procedure in a function that gets executed by a standard SELECT query? - oracle

I am following these steps, but I continue to get an error and don't see the issue:
1) Create a custom Oracle datatype that represents the database columns that you want to retrieve:
CREATE TYPE my_object AS OBJECT
(COL1 VARCHAR2(50),
COL2 VARCHAR2(50),
COL3 VARCHAR2(50));
2) Create another datatype that is a table of the object you just created:
TYPE MY_OBJ_TABLE AS TABLE OF my_object;
3) Create a function that returns this table. Also use a pipeline clause so that results are pipelined back to the calling SQL, for example:
CREATE OR REPLACE
FUNCTION MY_FUNC (PXOBJCLASS varchar2)
RETURN MY_OBJ_TABLE pipelined IS
TYPE ref1 IS REF CURSOR
Cur1 ref1,
out_rec_my_object := my_object(null,null,null);
myObjClass VARCHAR2(50);
BEGIN
myObjClass := PXOBJCLASS
OPEN Cur1 For ‘select PYID, PXINSNAME, PZINSKEY from PC_WORK where PXOBJCLass = ;1’USING myObjClass,
LOOP
FETCH cur1 INTO out_rec.COL1, out_rec.COL2, out_rec.COL3;
EXIT WHEN Cur1%NOTFOUND;
PIPE ROW (out_rec);
END LOOP;
CLOSE Cur1;
RETURN;
END MY_FUNC;
NOTE: In the example above, you can easily replace the select statement with a call to another stored procedure that returns a cursor variable.
4) In your application, call this function as a table function using the following SQL statement:
select COL1, COL2, COL3 from TABLE(MY_FUNC('SomeSampletask'));

There is no need to use dynamic sql (dynamic sql is always a little bit slower) and there are too many variables declared. Also the for loop is much easier. I renamed the argument of the function from pxobjclass to p_pxobjclass.
Try this:
create or replace function my_func (p_pxobjclass in varchar2)
return my_obj_table pipelined
is
begin
for r_curl in (select pyid,pxinsname,pzinskey
from pc_work
where pxobjclass = p_pxobjclass) loop
pipe row (my_object(r_curl.pyid,r_curl.pxinsname,r_curl.pzinskey));
end loop;
return;
end;
EDIT1:
It is by the way faster to return a ref cursor instead of a pipelined function that returns a nested table:
create or replace function my_func2 (p_pxobjclass in varchar2)
return sys_refcursor
is
l_sys_refcursor sys_refcursor;
begin
open l_sys_refcursor for
select pyid,pxinsname,pzinskey
from pc_work
where pxobjclass = p_pxobjclass;
return l_sys_refcursor;
end;
This is faster because creating objects (my_object) takes some time.

I see two problems:
The dynamic query does not work that way, try this:
'select PYID, PXINSNAME, PZINSKEY from PC_WORK where PXOBJCLass ='''||PXOBJCLASS||''''
You don't need myObjClass, and it seems all your quotes are wrong.
The quoting on 'SomeSampletask'...
select COL1, COL2, COL3 from TABLE(MY_FUNC('SomeSampletask'));

Maybe I'm misunderstanding something here, but it seems like you want to be using a VIEW.

Related

ORACLE - Selecting Parameters for calling Procedure from Table

Is it possible to select the parameters for calling a procedure from the select statement?
EXECUTE PROCEDURE_NAME(para1,para2,para3,para4);
commit;
Is it possible to select para1,para2,para3,para4 from a select query?
EXECUTE PROCEDURE_NAME((SELECT PARA1,PARA2,PARA3,PARA4 FROM TABLEA))
COMMIT;
I do not have access to modify the procedure.
As a slight variation on what #vc74 suggested, you could just replace your EXECUTE command (which, assuming this is SQL*Plus or SQL Developer anyway, is just a wrapper for an anonymous block anyway) with an explicit anonymous block:
begin
for r in (SELECT PARA1,PARA2,PARA3,PARA4 FROM TABLEA) loop
PROCEDURE_NAME(r.PARA1,r.PARA2,r.PARA3,r.PARA4);
end loop;
end;
/
(I've left the bits from your original call uppercase and the new bits lower case mostly to distinguish them.)
Using a loop just means you don't need to declare local variables and select into those. It would also allow you to process multiple rows from the table, though I see form a comment you only expect one row. However, the flip side of that is it won't complain if there are no rows, or if there is more than one row, as the variable approach would do.
You could also use a record type to avoid declaring all the parameters separately:
declare
l_row tablea%rowtype;
begin
SELECT * into l_row FROM TABLEA;
PROCEDURE_NAME(l_row.PARA1,l_row.PARA2,l_row.PARA3,l_row.PARA4);
end;
/
This now does expect exactly one row to be found in the table.
You can call the functions in sql. So if you are able to create a function in your schema then you can do the following:
create a function function_name in your schema that calls the procedure procedure_name and returns some dummy result
use this function in sql query: select function_name(para1,para2,para3,para4) from tablea
example of function:
create or replace function function_name(
p1 varchar2,
p2 varchra2,
p3 varchar2,
p4 varchar2
) return number
is
begin
procedure_name(p1,p2,p3,p4); -- here you execute the procedure
return null;
end;

How to run Oracle function which returns more than one value

My test function is this
CREATE OR REPLACE FUNCTION MULTI_VAL
(MYNAME OUT EMP2017.ENAME%TYPE)
RETURN NUMBER AS
MYSAL EMP2017.SAL%TYPE;
BEGIN
SELECT SAL, ENAME INTO MYSAL, MYNAME FROM EMP2017 ;
RETURN MYSAL;
END;
/
When I run it like
variable mynm varchar2(20)
SELECT MULTI_VAL(:mynm) FROM dual;
it gives this error
ERROR at line 1:
ORA-06553: PLS-561: character set mismatch on value for parameter 'MYNAME'
The error you get now indicates a datatype mismatch.
However there is a fundamental problem with your code. We cannot use functions which have OUT parameters in SQL. So once you have fixed the datatype issue you will get this error: ORA-06572: Function MULTI_VAL has out arguments.
You can run it like this:
declare
n varchar2(20);
x number;
begin
x := multi_val(n);
end;
/
Generally, functions with OUT parameters are considered bad practice. The syntax allows them, but the usage is hard to understand. It's better to use a procedure with two OUT parameters (because we can only call the program in PL/SQL anyway) or else have the function return a user-defined type.
CREATE TABLE EMP2017(ENAME VARCHAR2(10),SAL NUMBER);
INSERT INTO EMP2017 VALUES ('SMITH',5000);
INSERT INTO EMP2017 VALUES ('JOHNS',1000);
COMMIT;
CREATE TYPE RET_MULT AS OBJECT
(ENAME VARCHAR2(10),SAL NUMBER);
CREATE TYPE T_RET_MULT AS TABLE OF RET_MULT;
CREATE OR REPLACE FUNCTION MULTI_VAL RETURN T_RET_MULT PIPELINED IS
MYSAL RET_MULT;
BEGIN
FOR I IN(SELECT SAL, ENAME FROM EMP2017) LOOP
MYSAL := RET_MULT(I.ENAME,I.SAL);
PIPE ROW(MYSAL);
END LOOP ;
RETURN ;
END;
SELECT * FROM TABLE(MULTI_VAL());
I think this question can be solved without using pipeline functions. Just like this. All pre required data as described #Sedat.Turan except function. Sorry for copy/past.
CREATE TABLE EMP2017(ENAME VARCHAR2(10),SAL NUMBER);
INSERT INTO EMP2017 VALUES ('SMITH',5000);
INSERT INTO EMP2017 VALUES ('JOHNS',1000);
COMMIT;
CREATE TYPE RET_MULT AS OBJECT
(ENAME VARCHAR2(10),SAL NUMBER);
CREATE TYPE T_RET_MULT AS TABLE OF RET_MULT;
create or replace function MULTI_VAL return T_RET_MULT is
RET_SET T_RET_MULT;
begin
select RET_MULT(ENAME, SAL) bulk collect into RET_SET from EMP2017;
return RET_SET;
end;

PL/SQL Creating a procedure that contains result set joins

I want to create a procedure in PL/SQL that has 5 steps. Step 1 and 2 execute first and return an ID. In step 3, we have a SELECT statement that has a condition with that returned ID. I want then to take all of the results of that SELECT statement and use them in a JOIN in another SELECT statement and use THOSE results in a 3rd SELECT statement again using JOIN. From what I've seen, I can't use CURSOR in JOIN statements. Some of my co-workers have suggested that I save the results in a CURSOR and then use a loop to iterate through each row and use that data for the next SELECT. However since I'm going to do 2 selects this will create a huge fork of inside loops and that's exactly what I'm trying to avoid.
Another suggestion was to use Temprary Tables to store the data. However this procedure could be executed at the same time by many users and the table's data would conflict with each other. Right now I'm looking at LOCAL Temporary tables that supposedly filter the data according the the session but I'm not really sure I want to create dummy tables for my procedures since I want to avoid leaving trash in the schema (this procedure is for a custom part of the application). Is there a standard way of doing this? Any ideas?
Sample:
DECLARE
USERID INT := 1000000;
TEXT1 VARCHAR(100);
TEXT_INDEX INT;
CURSOR NODES IS SELECT * FROM NODE_TABLE WHERE DESCRIPTION LIKE TEXT || '%';
CURSOR USERS IS SELECT * FROM USERGROUPS JOIN NODES ON NODES.ID = USERGROUPS.ID;
BEGIN
SELECT TEXT INTO TEXT1 FROM TABLE_1 WHERE ID = USERID;
TEXT_INDEX = INSTR(TEXT, '-');
TEXT = SUBSTR(TEXT, 0, TEXT_INDEX);
OPEN NODES;
OPEN USERS;
END;
NOTE: This does NOT work. Oracle doesn't support joins between cursors.
NOTE2: This CAN be done in a single query but for the sake of argument (and in my real use case) I want to break those steps down in a procedure. The sample code is a depiction of what I'm trying to achieve IF joins between cursors worked. But they don't and I'm looking for an alternative.
I ended up using a function (although a procedure could be used as well) along with tables. Things I've learned and one should pay attention to:
PL/SQL functions can only return types that have been declared in the schema in advance and are clear. You can't create a function that returns something like MY_TABLE%ROWTYPE, even though it seems the type information is available it is not acceptable. You have to instead create a custom type of MY_TABLE%ROWTYPE is you want to return it.
Oracle treats tables of declared types differently from tables of %ROWTYPE. This confused the hell out of me at first but from what I've gathered this is how it works.
DECLARE TYPE MY_CUSTOM_TABLE IS TABLE OF MY_TABLE%ROWTYPE;
Declares a collection of types of MY_TABLE row. In order to add to this we must use BULK COLLECT INTO from an SQL statement that queries MY_TABLE. The resulting collection CANNOT be used in JOIN statements is not queryable and CANNOT be returned by a function.
DECLARE
CREATE TYPE MY_CUSTOM_TYPE AS OBJECT (COL_A NUMBER, COL_B NUMBER);
CREATE TYPE MY_CUSTOM_TABLE AS TABLE OF MY_CUSTOM_TYPE;
my_custom_tab MY_CUSTOM_TABLE;
This create my_custom_tab which is a table (not a collection) and if populated can be queried at using TABLE(my_custmo_tab) in the FROM statement. As a table which is declared in advance in the schema this CAN be returned from a function. However it CANNOT be populated using BULK COLLECT INTO since it is not a collection. We must instead use the normal SELECT INTO statement. However, if we want to populate it with data from an existing table that has 2 number columns we cannot simply do SELECT * INTO my_custom_tab FROM DOUBLE_NUMBER_TABLE since my_custom_tab hasn't been initialized and doesn't contain enough rows to receive the data. And if we don't know how many rows a query returns we can't initialize it. The trick into populating the table is to use the CAST command and cast our select result set as a MY_CUSTOM_TABLE and THEN add it.
SELECT CAST(MULTISET(SELECT COL_A, COL_B FROM DOUBLE_NUMBER_TABLE) AS MY_CUSTOM_TABLE) INTO my_custom_tab FROM DUAL
Now we can easily use my_custom_tab in queries etc through the use of the TABLE() function.
SELECT * FROM TABLE(my_custom_tab)
is valid.
You can do such decomposition in many ways, but all of them have a significant performance penalty in comaration with single SQL statement.
Maintainability improvement are also questionable and depends on specific situation.
To review all possibilities please look through documentation.
Below is some possible variants based on simple logic:
calculate Oracle user name prefix based on given Id;
get all users whose name starts with this prefix;
find all tables owned by users from step 2;
count a total number of found tables.
1. pipelined
Prepare types to be used by functions:
create or replace type TUserRow as object (
username varchar2(30),
user_id number,
created date
)
/
create or replace type TTableRow as object (
owner varchar2(30),
table_name varchar2(30),
status varchar2(8),
logging varchar2(3)
-- some other useful fields here
)
/
create or replace type TUserList as table of TUserRow
/
create or replace type TTableList as table of TTableRow
/
Simple function to find prefix by user id:
create or replace function GetUserPrefix(piUserId in number) return varchar2
is
vUserPrefix varchar2(30);
begin
select substr(username,1,3) into vUserPrefix
from all_users
where user_id = piUserId;
return vUserPrefix;
end;
/
Function searching for users:
create or replace function GetUsersPipe(
piNameStart in varchar2
)
return TUserList pipelined
as
vUserList TUserList;
begin
for cUsers in (
select *
from
all_users
where
username like piNameStart||'%'
)
loop
pipe row( TUserRow(cUsers.username, cUsers.user_id, cUsers.created) ) ;
end loop;
return;
end;
Function searching for tables:
create or replace function GetUserTablesPipe(
piUserNameStart in varchar2
)
return TTableList pipelined
as
vTableList TTableList;
begin
for cTables in (
select *
from
all_tables tab_list,
table(GetUsersPipe(piUserNameStart)) user_list
where
tab_list.owner = user_list.username
)
loop
pipe row ( TTableRow(cTables.owner, cTables.table_name, cTables.status, cTables.logging) );
end loop;
return;
end;
Usage in code:
declare
vUserId number := 5;
vTableCount number;
begin
select count(1) into vTableCount
from table(GetUserTablesPipe(GetUserPrefix(vUserId)));
dbms_output.put_line('Users with name started with "'||GetUserPrefix(vUserId)||'" owns '||vTableCount||' tables');
end;
2. Simple table functions
This solution use same types as a variant with pipelined functions above.
Function searching for users:
create or replace function GetUsers(piNameStart in varchar2) return TUserList
as
vUserList TUserList;
begin
select TUserRow(username, user_id, created)
bulk collect into vUserList
from
all_users
where
username like piNameStart||'%'
;
return vUserList;
end;
/
Function searching for tables:
create or replace function GetUserTables(piUserNameStart in varchar2) return TTableList
as
vTableList TTableList;
begin
select TTableRow(owner, table_name, status, logging)
bulk collect into vTableList
from
all_tables tab_list,
table(GetUsers(piUserNameStart)) user_list
where
tab_list.owner = user_list.username
;
return vTableList;
end;
/
Usage in code:
declare
vUserId number := 5;
vTableCount number;
begin
select count(1) into vTableCount
from table(GetUserTables(GetUserPrefix(vUserId)));
dbms_output.put_line('Users with name started with "'||GetUserPrefix(vUserId)||'" owns '||vTableCount||' tables');
end;
3. cursor - xml - cursor
It's is a specific case, which may be implemented without user-defined types but have a big performance penalty, involves unneeded type conversion and have a low maintainability.
Function searching for users:
create or replace function GetUsersRef(
piNameStart in varchar2
)
return sys_refcursor
as
cUserList sys_refcursor;
begin
open cUserList for
select * from all_users
where username like piNameStart||'%'
;
return cUserList;
end;
Function searching for tables:
create or replace function GetUserTablesRef(
piUserNameStart in varchar2
)
return sys_refcursor
as
cTableList sys_refcursor;
begin
open cTableList for
select
tab_list.*
from
(
XMLTable('/ROWSET/ROW'
passing xmltype(GetUsersRef(piUserNameStart))
columns
username varchar2(30) path '/ROW/USERNAME'
)
) user_list,
all_tables tab_list
where
tab_list.owner = user_list.username
;
return cTableList;
end;
Usage in code:
declare
vUserId number := 5;
vTableCount number;
begin
select count(1) into vTableCount
from
XMLTable('/ROWSET/ROW'
passing xmltype(GetUserTablesRef(GetUserPrefix(vUserId)))
columns
table_name varchar2(30) path '/ROW/TABLE_NAME'
)
;
dbms_output.put_line('Users with name started with "'||GetUserPrefix(vUserId)||'" owns '||vTableCount||' tables');
end;
Of course, all variants may be mixed, but SQL looks better at least for simple cases:
declare
vUserId number := 5;
vUserPrefix varchar2(100);
vTableCount number;
begin
-- Construct prefix from Id
select max(substr(user_list.username,1,3))
into vUserPrefix
from
all_users user_list
where
user_list.user_id = vUserId
;
-- Count number of tables owned by users with name started with vUserPrefix string
select
count(1) into vTableCount
from
all_users user_list,
all_tables table_list
where
user_list.username like vUserPrefix||'%'
and
table_list.owner = user_list.username
;
dbms_output.put_line('Users with name started with "'||vUserPrefix||'" owns '||vTableCount||' tables');
end;
P.S. All code only for demonstration purposes: no optimizations and so on.

Return table from function in Oracle

Following function works with SQL Server.
CREATE FUNCTION GET_EMP_PROB_START_ATT_CODE(#EVAL_TYPE VARCHAR(6))
RETURNS #EMP_PROB_START_ATT_CODE TABLE (
PROBATION_START_ATT_CODE varchar(6) NULL
)
AS
BEGIN
IF #EVAL_TYPE='New'
INSERT INTO #EMP_PROB_START_ATT_CODE (PROBATION_START_ATT_CODE)
SELECT NEW_EMP_PROB_START_ATT_CODE FROM HS_HR_PEA_DYNAMIC_ATTRIBUTES;
ELSE
INSERT INTO #EMP_PROB_START_ATT_CODE (PROBATION_START_ATT_CODE)
SELECT EXIS_EMP_PROB_START_ATT_CODE FROM HS_HR_PEA_DYNAMIC_ATTRIBUTES;
RETURN;
END;
I just want to convert this to Oracle equivalent query . Tried but not succeeded.
CREATE FUNCTION GET_EMP_PROB_START_ATT_CODE(EVAL_TYPE VARCHAR(6))
RETURN EMP_PROB_START_ATT_CODE IS TABLE
PROBATION_START_ATT_CODE VARCHAR(6) NULL;
AS
BEGIN
IF EVAL_TYPE='New'
INSERT INTO EMP_PROB_START_ATT_CODE (PROBATION_START_ATT_CODE)
SELECT NEW_EMP_PROB_START_ATT_CODE FROM HS_HR_PEA_DYNAMIC_ATTRIBUTES;
ELSE
INSERT INTO EMP_PROB_START_ATT_CODE (PROBATION_START_ATT_CODE)
SELECT EXIS_EMP_PROB_START_ATT_CODE FROM HS_HR_PEA_DYNAMIC_ATTRIBUTES;
RETURN;
END;
Warning: compiled but with compilation errors
Any help guys..
First of all, create a database-wide type:
create type string_tab6 is table of varchar2(6);
Then you would create your function like so:
create or replace function get_emp_prob_start_att_code(eval_type varchar2)
return string_tab6
is
v_array string_tab6;
begin
if eval_type = 'New' then
select new_emp_prob_start_att_code
bulk collect into v_array
from hs_hr_pea_dynamic_attributes;
else
select exis_emp_prob_start_att_code
bulk collect into v_array
from hs_hr_pea_dynamic_attributes;
end if;
return v_array;
end get_emp_prob_start_att_code;
/
However, I would question why you need such a function. What are you going to use it for?
In Oracle, I'd expect to see that logic embedded directly into whichever SQL statement needs that info, which you could easily do via a case statement.
First define row type. For existing database table you can use %ROWTYPE.
Then define table type.
Finally use the table type as return type of the function.
TYPE tr_row IS my_table%ROWTYPE;
TYPE tab_row IS TABLE OF tr_row;
FUNCTION get_row RETURN tab_row IS
mytab tab_row;
BEGIN
SELECT * FROM my_table
BULK COLLECT INTO mytab;
RETURN mytab;
END;

Returning Oracle ref cursor and appending multiple results

I have this problem I'm hoping someone knows the answer to. I have an oracle stored procedure that takes a customer id and returns all the customer's orders in a ref_cursor. Oversimplifying it, this is what I have:
Orders
- orderId
- siteID
Customers
- siteID
- Name
GetOrder(siteID, outCursor) /* returns all orders for a customer */
Now, I need to write another procedure that takes a customer name and does a LIKE query to get all custIds, then I need to reuse the GetOrder method to return all the orders for the custIds found, something like this:
PROCEDURE GetOrderbyCustName(
p_name IN VARCHAR2,
curReturn OUT sys_refcursor
)
IS
siteid number;
BEGIN
FOR rec in SELECT site_id FROM customers WHERE name LIKE p_name
LOOP
-- This will replace curReturn in each iteration
-- how do I append instead?
GetOrder(rec.site_id,
curReturn
);
END LOOP;
END GetOrderbyCustName;
My question is, how do I append the return of GetOrder to curReturn in each iteration? As it's written right now it overwrites it in each cycle of the loop.
Thanks!!
You can't do it like that - cursors cannot be appended or merged. Just do this instead:
PROCEDURE GetOrderbyCustName(
p_name IN VARCHAR2,
curReturn OUT sys_refcursor
)
IS
BEGIN
OPEN curReturn FOR
SELECT o.orderID, o.siteID
FROM Orders o
JOIN Customers c ON c.siteID = o.siteID
WHERE c.name LIKE p_name;
END GetOrderbyCustName;
If the query is simple, I would say go with Tony's answer. This is not only simple but likely to perform better than executing one query for each siteID.
If it is fairly complex then it might be worth some extra effort to reuse the GetOrder procedure so you only have to maintain one query.
To do this, you would need to actually fetch the data from the refcursor on each iteration of the loop, and put it into some other data structure.
One option, if it makes sense for the interface, is to change GetOrderbyCustName to have a PL/SQL index-by table as its output parameter instead of a refcursor. Append to that table on each iteration through the loop.
If you really need to return a refcursor, you can use a nested table type instead and then return a cursor querying that nested table. Something like this (not tested code):
CREATE TYPE number_table_type AS TABLE OF NUMBER;
PROCEDURE GetOrderbyCustName(
p_name IN VARCHAR2,
curReturn OUT sys_refcursor
)
IS
cursor_source_table number_table_type := number_table_type();
single_site_cursor sys_refcursor;
orderID NUMBER;
BEGIN
FOR rec in SELECT site_id FROM customers WHERE name LIKE p_name
LOOP
-- This will replace curReturn in each iteration
-- how do I append instead?
GetOrder(rec.site_id,
single_site_cursor
);
-- Fetch all rows from the refcursor and append them to the nested table in memory
LOOP
FETCH single_site_cursor INTO orderID;
EXIT WHEN single_site_cursor%NOTFOUND;
cursor_source_table.extend();
cursor_source_table( cursor_source_table.COUNT+1) := orderID;
END LOOP;
END LOOP;
OPEN curReturn FOR
SELECT * FROM TABLE( cursor_source_table );
END GetOrderbyCustName;

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