Execute immediate -- udpate statement

Question

Hello,
I am fairly new to scripting sql..pl/sql.. any help will be really appreciated!!
I have a table where i am trying to update one of the column with table name i am passing dynamically.
However i get the invalid identifier error. ORA-00904. The column AD.MIR_PARENT i am updating is of compatible data type.
Any help please.. where i am doing a mistake..
fyi -- the reason i am updating the column with table name is because i need to know which table i make a hit.
DECLARE
p_table varchar2(200);
P_SCHEMA varchar2(200);
p_acct NUMBER;
v_acct NUMBER;
P_column varchar2(200);
cursoR c is
select schema_name, table_name, column_name from addnl_sources where TABLE_NAME = 'ACCT';
    BEGIN
        FOR R IN C LOOP
                                p_TABLE := R.TABLE_NAME;
                                P_SCHEMA := R.SCHEMA_NAME;
                                P_column := R.column_name;
                   execute immediate 'UPDATE ACCT_DELETE AD
            SET AD.MIR_PARENT = '||p_table || '
            WHERE EXISTS (select "'||p_table || '" from "' || P_SCHEMA||'"."'||p_table || '" where "' || P_column ||'" = ad.acct_id )
            AND AD.EXCLUDE IS NULL
            AND AD.ACCT_ID = 472039
            AND AD.MIR_PARENT IS NULL' ;
                        END LOOP;
    end;Edited by: 982806 on Jan 18, 2013 10:47 AM
Edited by: 982806 on Jan 18, 2013 11:04 AM

Answer 1

Welcome to the forum!
Whenever you post provide your 4 digit Oracle version (result of SELECT * FROM V$VERSION)
>
I am fairly new to scripting sql..pl/sql.. any help will be really appreciated!!
I have a table where i am trying to update one of the column with table name i am passing dynamically.
However i get the invalid identifier error. ORA-00904. The column AD.MIR_PARENT i am updating is of compatible data type.
Any help please.. where i am doing a mistake..
>
Just about everything you are doing is a mistake.
1. You using PL/SQL instead of SQL to do this job? That is usually a red flag that something is wrong about what you are trying to do or how you are trying to do it.
2. You are 'fairly new to scripting' and have chosen to use dynamic sql? That is one of the harder techniques to learn and to use properly and is another red flag. Experienced professionals often don't use dynamic sql properly and often use it when they shouldn't.
3. You are using a loop to execute against multiple tables? It is extremely difficult to perform proper error handling and recovery when you do this. What if some of the tables get updated and others don't? How will you know which ones still need to be updated? How will you roll back the data if you need to.
4. You have opened a GIGANTIC opportunity for sql injection where the wrong tables could accidentally be updated. That could corrupt the data and reek havoc on the system. Anyone could, accidentally or intentionally, put the wrong schema, table or column in your lookup table and cause enormous damage.
5. You are using double quotes in PL/SQL? Where did you learn that?
            WHERE EXISTS (select "'||p_table || '" from "' || P_SCHEMA||'"."'||p_table || '" where "' || P_column ||'" = ad.acct_id ) Finally, it is standard practice when you do have a use case for dynamic sql to construct the query in a variable and then print the query or write it to a log file so it can be tested independently.
If you do that you will likely see your error.
query VARCHAR2(4000);
query := 'UPDATE . . .';
execute immediate query;SUMMARY: don't try to automate something until you can first do it manually. Write a query that works properly first. Then, and only then, convert it to dynamic sql.