Dynamic SQL syntax using EXECUTE IMMEDIATE - oracle

Dynamic SQL update statement as below:
EXECUTE IMMEDIATE 'UPDATE '||l_prefix||'CRS_CUSTOMERS SET CUSTOMER_SOURCE_REF_ID = '||i.CUSTOMER_REF_ID||' WHERE CUSTOMER_ID = '||i.CUSTOMER_ID;
l_prefix is the parameter hold the prefix of table name, the value assigned is T_
i.CUSTOMER_REF_ID and i.CUSTOMER_ID are the fields fetched from cursor.
The dynamic statement encounter error ORA-00904: invalid identifier when data fetched.
When rewrite it in static way, the query is working fine:
UPDATE T_CRS_CUSTOMERS SET CUSTOMER_SOURCE_REF_ID = i.CUSTOMER_REF_ID WHERE
CUSTOMER_ID = i.CUSTOMER_ID;
I know it must be something wrong on the concatenation of dynamic SQL, just couldn't pinpoint any as the compilation is fine.

WARNING: Dynamic SQL like this is susceptible to SQL Injection attacks. Wherever possible rewrite your dynamic SQL to use bind variables instead.
Instead of constructing your dynamic SQL like this:
L_SQL := 'UPDATE '||l_prefix||'CRS_CUSTOMERS SET CUSTOMER_SOURCE_REF_ID = '||i.CUSTOMER_REF_ID||' WHERE CUSTOMER_ID = '||i.CUSTOMER_ID;
EXECUTE IMMEDIATE L_SQL;
Use this:
L_SQL := 'UPDATE '||l_prefix||'CRS_CUSTOMERS SET CUSTOMER_SOURCE_REF_ID = :REF_ID WHERE CUSTOMER_ID = :CUST_ID';
EXECUTE IMMEDIATE L_SQL USING i.CUSTOMER_REF_ID, i.CUSTOMER_ID;
This is still subject to SQL injection at the l_prefix, but if you control that value programatically it may be OK. Also splitting the construction of the SQL and execution of the SQL into two steps allows you to more easily replace the EXECUTE IMMEDIATE with DBMS_OUTPUT.PUT_LINE(SQL); to check your query for syntax errors. You can also want to DBMS_OUTPUT.PUT_LINE your parameters i.CUSTOMER_REF_ID and i.CUSTOMER_ID to check their values.

Related

Oracle Apex - include user on execute immediate query

I have the following query for an execute immediate:
begin
execute immediate q'['delete from MY_TABLE where USER_EMAIL =
lower(v('APP_USER'))]';
end;
But I'm getting this error:
ora_sqlcode: 00900 Invalid SQL Statement
Anybody knows how can I include the user in there?
Thanks
That's completely invalid statement, it isn't application user that makes it wrong.
Try
execute immediate q'[delete from MY_TABLE where USER_EMAIL = lower(v('APP_USER'))]';
or
execute immediate 'delete from my_table where user_email = ' || lower(:APP_USER);
On the other hand, why do you want to use dynamic SQL? There's nothing dynamic here, so ordinary
delete from my_table where user_email = lower(:APP_USER);
would do.

How to assign variables using dynamic sql

I need to assign two variables(tmp_x and tmp_y) with dynamic sql, because I need to select the right table at runtime. the sql as below:
updateSql:= 'select p.gis_x,p.gis_y into tmp_x,tmp_y from publish_'
||splitCollection(indexs).city_no ||'.t_customer p
where p.customer_id=:1 and p.gis_x is not null and p.gis_y is not null';
execute immediate updateSql using splitCollection(indexs).CUSTOMER_ID;
the compilation is OK ,but occur the runtime error about "lack of keyword", how can I fix that?
So, following the comments:
This:
updateSql:= 'select p.gis_x,p.gis_y into tmp_x,tmp_y from publish_'
||splitCollection(indexs).city_no ||'.t_customer p
where p.customer_id=:1 and p.gis_x is not null and p.gis_y is not null';
execute immediate updateSql using splitCollection(indexs).CUSTOMER_ID;
Needs to become:
updateSql:= 'select p.gis_x,p.gis_y from publish_'
||splitCollection(indexs).city_no ||'.t_customer p
where p.customer_id=:1 and p.gis_x is not null and p.gis_y is not null';
execute immediate updateSql using splitCollection(indexs).CUSTOMER_ID RETURNING into tmp_x,tmp_y;
The difference is the into clause, which, when used with execute immediate should go in the actual statement and not be part of the Select statement.
Cheers

ORACLE: Cursor with dynamic query - throws error "invalid identifier" for cursor field

I have a logic to implement where I have to use dynamic sql(column names and where clause is decided on the fly).So here my cursor(emp_ref_cursor) has a dynamic sql, and has 3 cursor fields(emp_id,emp_name,dept).
Using these cursor fields in WHERE clause I am trying to execute another dynamic sql inside the loop.Bt oracle isn't able to identify the cursor field and throws an error like "ORA-00904: "EMP_REC"."EMP_ID": invalid identifier" though I am able to output emp_rec.emp_id through DBMS_OUTPUT.
NOTE: Please don't comment on the code quality this is not the actual code.
This is just used to describe the problem. I can't post the actual code due to
some compliance related stuff.
DECLARE
emp_ref_cursor sys_refcursor;
v_sql varchar2(3900);
TYPE emp_rec_type IS RECORD (emp_id number,emp_name varchar2(100),dept_id varchar2(100));
emp_rec emp_rec_type;
v_dept_id number:='1234';
v_dob varchar2(100);
v_desig varchar2(100);
x_dynamic_col_1 varchar2(100):='dob'; --dynamic column(based on some condition)
x_dynamic_col_2 varchar2(100):='designation'; --dynamic column(based on some condition)
x_dynamic_col_3 varchar2(100):='emp_id'; --dynamic column(based on some condition)
BEGIN
v_sql:='SELECT emp_id,emp_name,dept FROM employee WHERE dept_id=' || v_dept_id;
OPEN emp_ref_cursor FOR v_sql;
LOOP
FETCH emp_ref_cursor INTO emp_rec;
exit WHEN emp_ref_cursor%NOTFOUND;
stmt:='SELECT ' || x_dynamic_col_1 || ',' || x_dynamic_col_2 || '
FROM employee A
WHERE emp_id=emp_rec.' || x_dynamic_col_3;
DBMS_OUTPUT.PUT_LINE(stmt);
--Prints the SQL query as expected
DBMS_OUTPUT.PUT_LINE('emp_rec.emp_id:'||emp_rec.emp_id);
--Displays the value!!!
execute immediate stmt into v_dob, v_desig;
--But why is it saying emp_rec.emp_id is invalid identifier??
END LOOP;
END;
You have emp_rec defined as a local PL/SQL variable. None of the PL/SQL data is in scope to the dynamic SQL execution. When it is executed it as if you tried to run the statement - as it is displayed by your dbms_output standalone in a separate SQL context. If you did that it would be clear that emp_rec doesn't exist to the query.
You refer to it you would need to use a bind variable:
WHERE emp_id=:dynamic_col_3';
And then execute it with:
execute immediate stmt using emp_rec.emp_id;
But you can't use the x_dynamic_col_3 local variable in the using clause. Since - in this example anyway - the query would also need to change to use a different table column is the dynamic record field changed - that doesn't seem too much of a problem. But you said the where clause will change on the fly too. In that case you could have another local variable that you set to the relevant x field before the executin.
You have incorrect using of EXECUTE IMMEDIATE. You don't need to put INTO clause to SQL query. Use this instead:
stmt:='SELECT ' || x_dynamic_col_1 || ',' || x_dynamic_col_2 || '
FROM employee A
WHERE emp_id=emp_rec.' || x_dynamic_col_3;
execute immediate stmt into v_dob, v_desig;

Oracle pl sql dynamic using clause

I have a question about "dynamic using clause" in execute immediate statement. I need to set dynamically the "execute immediate statement" and the using clause as well. I don't know the table structure, but I know only the name of the table, and I need to do an operation update on it.
So I wrote a function (through user_tab_columns and user user_constraints tables) to set a variable with the update statement and the bind_variable but now I need to set the using clause with the list of variable.
Example:
CREATE TABLE table1
(
rec1 VARCHAR2(10 BYTE) NULL,
rec2 DATE NULL,
rec3 number(9) not null
);
declare
TYPE cur_type IS REF CURSOR;
cur cur_type;
table_list table1%ROWTYPE;
sqlstring varchar2(400);
begin
OPEN cur FOR sqlstring;
LOOP
FETCH cur INTO table_list;
EXIT WHEN cur%NOTFOUND;
sqlstring:=function1('table1');
-- that returns sqlstring:='update table1 set rec1=:1 , rec2=:2 , rec3=:3 where rec_id=:c4';
execute immediate sqlstring using table_list.rec1, table_list.rec2, table_list.rec3, table_list.rec_id;
END LOOP;
close cur;
end;
I need to implement dynamically the list of variables of the cursor table_list.
"execute immediate sqlstring using table_list.rec1, table_list.rec2, table_list.rec3, table_list.rec_id"
Does anybody know how to solve this problem?
Thanks a lot for your replies.
The problem is that I'm assuming I don't know the table's structure and so the list of variables of the cursor table_list table1%ROWTYPE.
So I can't explicit table_list.rec1, table_list.rec2 ... in the using clause.
If I use only table_list as variable
begin
OPEN cur FOR sqlstring;
LOOP
FETCH cur INTO table_list;
EXIT WHEN cur%NOTFOUND;
sqlstring:=function1('table1');
execute immediate sqlstring using table_list;
END LOOP;
close cur;
I got the error:" 00457 Expressions have to be of SQL types"
http://psoug.org/oraerror/PLS-00457.htm
Error Cause:
An expression of wrong type is in USING or dynamic RETURNING clause. In USING or dynamic RETURNING clause, an expression cannot be of non-SQL types such as BOOLEAN, INDEX TABLE, and record.
I need a way to retrive not only the values but also the list of variables of the cursor table_list first.
But maybe it's impossible and I have to find a work around.
If I will find something interesting I will post.
Thankyou.
Try to replace your execute immediate to full use of dbms_sql.
http://docs.oracle.com/cd/B28359_01/appdev.111/b28419/d_sql.htm#i996891
And usefull for you will be bind_array function from this package.
Use dynamic PL/SQL, unless you can re-factor the original statement and just plug the values into it.
declare
v_string constant varchar2(32767) := 'update test1 set a = :1, b = :2';
v_using_string varchar2(32767);
begin
--Create dynamic using string.
--For example, let's say you want to pass in the values "1" for each NUMBER column.
select listagg(1, ',') within group (order by null)
into v_using_string
from user_tab_columns
where table_name = 'TEST1'
and data_type = 'NUMBER';
--Execute the original dynamic SQL, adding the USING string.
execute immediate '
begin
execute immediate '''||v_string||''' using '||v_using_string||';
end;
';
end;
/
You can either use DBMS_SQL package:
open a cursor using dbms_sql.open_cursor
parse the statement using dbms_sql.parse
bind variables in a loop using dbms_sql.bind_variable
execute the statement using dbms_sql.execute
and finally close the cursor using dbms_sql.close_cursor
Or EXECUTE IMMEDIATE of anonymous PL/SQL block, which performs a dynamically created EXECUTE IMMEDIATE (this approach is not suitable for returning data). See Answer of #JonHeller.

Re-using bind variables in Oracle PL/SQL

I have a hefty SQL statement with unions where code keeps getting re-used. I was hoping to find out if there is a way to re-use a single bind variable without repeating the variable to for "USING" multiple times.
The code below returns "not all variables bound" until I change the "USING" line to "USING VAR1,VAR2,VAR1;"
I was hoping to avoid that as I'm referring to :1 in both instances - any ideas?
declare
var1 number :=1;
var2 number :=2;
begin
execute immediate '
select * from user_objects
where
rownum = :1
OR rownum = :2
OR rownum = :1 '
using var1,var2;
end;
/
EDIT: For additional info, I am using dynamic SQL as I also generate a bundle of where conditions.
I'm not great with SQL arrays (I am using a cursor in my code but I think that will overcomplicate the issue) but the pseudocode is:
v_where varchar2(100) :='';
FOR i in ('CAT','HAT','MAT') LOOP
v_where := v_where || ' OR OBJECT_NAME LIKE ''%' || i.string ||'%''
END;
v_where := ltrim(v_where, ' OR');
And then modifying the SQL above to something like :
execute immediate '
select * from user_objects
where
rownum = :1
OR rownum = :2
OR rownum = :1 AND ('||V_WHERE||')'
using var1,var2;
There are some options you might consider, although they may require changes, either to how you execute your SQL statement or to your SQL statement itself.
Use DBMS_SQL instead of EXECUTE IMMEDIATE -- DBMS_SQL (see http://docs.oracle.com/cd/B19306_01/appdev.102/b14258/d_sql.htm) is harder to use than EXECUTE IMMEDIATE, but gives you more control over the process -- including the ability (through DBMS_SQL.BIND_VARIABLE and DBMS_SQL.BIND_ARRAY) to bind by name instead of by position.
Use EXECUTE IMMEDIATE with a WITH clause -- You might be able restructure your query to use WITH clause that gathers your bind variables in subquery at the beginning, and then joins to the subquery (instead of referencing the bind variables directly) whenever it needs them. It might look something like this
with your_parameters as
(select :1 as p1, :2 as p2 from dual)
select *
from your_table, your_parameters
where your_table.some_column1 = your_parameters.p1
and your_table.some_column2 <= your_parameters.p1
and your_table.some_column3 = your_parameters.p2
This could affect the performance of your query, but it might be an acceptable compromise.
Don't use dynamic SQL -- Of course, if you don't need dynamic SQL, you don't need to use EXECUTE IMMEDIATE, so the "bind only by position" limitiation does not apply. Are you sure you really need to use dynamic SQL?
EDIT: If you're using dynamic SQL because you have a variable number of OR conditions like you posted in your edit, you might be able to avoid using dynamic SQL by doing one of the following:
If the OR criteria come from a table (or query) -- Join to that table (or query) instead of using a list of OR criteria. For example, if CAT, HAT, and MAT are listed in a column named YOUR_CRITERIA in a table named YOUR_CRITERIA_TABLE you might add YOUR_CRITERIA_TABLE to the FROM clause and replace the OBJECT_NAME LIKE '%CAT% OR OBJECT_NAME LIKE '%MAT% OR OBJECT_NAME LIKE '%HAT% OR OBJECT_NAME LIKE '%MAT% in the WHERE clause with something like OBJECT_NAME LIKE '%' || YOUR_CRITERIA_TABLE.YOUR_CRITERIA || '%'.
Otherwise, you might put the criteria in a global temporary table -- If your criteria don't come from a table (or query), you could (once, at design time, not at run time) create a global temporary table to hold them, and then at run time, insert the criteria into the global temporary table and then join to it as described in item 1.
Or, you might put the criteria in an nested table -- This is like item 2, except uses a nested table (one created using CREATE TYPE...IS TABLE OF) instead of a global temporary table. You could create or own nested table type, or use a built-in one like SYS.ODCIVARCHAR2LIST. In PL/SQL, you would populate an variable of this type, and then use it like a "real" table like in item 1.
An example of item 3 might look something like:
DECLARE
tblCriteria SYS.ODCIVARCHAR2LIST;
BEGIN
tblCriteria := SYS.ODCIVARCHAR2LIST();
-- In "real" code you might populate the nested table in a loop.
-- This example populates it explicitly so that it will compile. For the
-- purpose of the example, we could have populated the nested table in
-- a single statement:
-- tblCriteria := SYS.ODCIVARCHAR2LIST('CAT', 'HAT', 'MAT');
tblCriteria.EXTEND(1);
tblCriteria(tblCriteria.LAST) := 'CAT';
tblCriteria.EXTEND(1);
tblCriteria(tblCriteria.LAST) := 'HAT';
tblCriteria.EXTEND(1);
tblCriteria(tblCriteria.LAST) := 'MAT';
FOR rec IN
(
SELECT
USER_OBJECTS.*
FROM
USER_OBJECTS,
TABLE(tblCriteria) YOUR_NESTED_TABLE
WHERE
USER_OBJECTS.OBJECT_NAME LIKE '%' || YOUR_NESTED_TABLE.COLUMN_VALUE || '%'
)
LOOP
-- Do something. For example, print out the object name.
DBMS_OUTPUT.PUT_LINE(rec.OBJECT_NAME);
END LOOP;
END;
No, unfortunately, the bind variables for EXECUTE IMMEDIATE must be provided in the same order they appear in the statement, and the bind variable names are ignored. So you'll just have to have :1, :2 and :3 in your statement.

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