Querying many tables at once from a select statement for specific values

Question

Hi all,
I'm very new to PL/SQL and have a daunting task ahead of me. I'm pretty sure our database normalization scheme is all out of whack, which I dont have the experience to fix yet, but this is the task ahead of me without getting to change or fix our structure:
in the universe has 1000+ tables.
need--> Some of those tables have fields that contain a value that has to be changed.
The only thing I have to go on is the column name will contain 'EMP'... but there is no specific naming convention for the column names.
When I search on:
select * from all_tab_columns where column_name like UPPER('%EMP%')
It returns 750 rows. (So 750 rows = 750 columns in 500 different tables (some tables have 2 or more columns in it))
tables names are random (table1, table2, etc).
columns names are random with EMP in it (column1,column2,etc).
I have 75 possible field values that I need to check each of those 750 columns for.
Maybe this is too messy, but I'm looking at subqueries, joins, arrays, cursors, etc, anything to minimize the amount of work I have to do.
I think this is too much to do a join with, but that seems to be what all the documentation is pointing me to.
can you point me to a simple example of what i could
write?
the logic i see it would be
run the select statement to grab the column names that meet EMP.
one at a time, search each column in the corresponding table for the 75 values.
return the results of rows for each column/table that meet one of the 75 unique values.
I'll have to also update each of the 75 values to (used to be values 1, 2, 3 ... to new values X1, X2, X3, etc.)
Any help at all would be very helpful,
aspiring pl/sql programmer but having a rough time of it

Answer 1

I think you're looking to do something like the following pseudocode:
BEGIN
    FOR tblrec IN (SELECT table_name, column_name
                     FROM all_tab_columns
                    WHERE column_name LIKE '%EMP%')
    LOOP
        FOR rec IN (SELECT ROWID
                      FROM tblrec.table_name
                     WHERE REGEXP_LIKE(tblrec.column_name, '(expr1|expr2|...)')
        LOOP
            DBMS_OUTPUT.PUT_LINE(
                'Found expression on ROWID ' || rec.rowid
                || ' in column ' || tblrec.column_name
                || ' on table ' || tblrec.table_name);
        END LOOP;
    END LOOP;
END;