set serveroutput on size 2000;
--PL/sql block to link ISSN in serial base on a company's ISSN text file

declare
    cursor ItemCursor is
        select issn is2 from web.obfuscated1 where issn is not null
            union
        select eissn is2 from web.obfuscated1 where eissn is not null;

    cursor ItemCursor1(aIS varchar2) is
        select obfuscated1_uid from web.obfuscated1 where group_num is null and issn in (
            select distinct issn from web.obfuscated1 where issn = aIS or eissn = aIS
                union
            select distinct eissn from web.obfuscated1 where issn = aIS or eissn = aIS
        )
            union
        select obfuscated1_uid from web.obfuscated1 where eissn in (
            select distinct issn from web.obfuscated1 where issn = aIS or eissn = aIS
                union
            select distinct eissn from web.obfuscated1 where issn = aIS or eissn = aIS
        );

    cursor ItemCursor2(aIS9 varchar2) is
        select obfuscated1_uid from web.obfuscated1 where issn in (
            select distinct issn from web.obfuscated1 where issn = aIS9 or eissn = aIS9
                union
            select distinct eissn from web.obfuscated1 where issn = aIS9 or eissn = aIS9
        ) and group_num is null;

    agroup      number(8);
    processCount    number(8);

    ------------------------------------------------------
    -- MAIN BLOCK -----------------------------------
    -------------------------------------------------
begin
    processCount := 0;

    agroup := null;
    for itemRec in ItemCursor loop
        agroup := null;
        begin
            select group_num into agroup from web.obfuscated1 where issn in (
                select distinct issn from web.obfuscated1 where issn = itemRec.is2 or eissn = itemRec.is2
                    union
                select distinct eissn from web.obfuscated1 where issn = itemRec.is2 or eissn = itemRec.is2
            ) and group_num is not null and issn is not null and eissn is not null and rownum <= 1;

        exception
            when no_data_found then
                agroup := null;
            when others then
                agroup := null;
        end;

        if agroup is not null then
            for itemRec2 in ItemCursor2(itemRec.is2) loop
                update web.obfuscated1 set group_num = agroup where obfuscated1_uid = itemRec2.obfuscated1_uid;
                commit;
            end loop;
        else
            processCount := processCount + 1;
            for itemRec1 in ItemCursor1(itemRec.is2) loop
                update web.obfuscated1 set group_num = processCount where obfuscated1_uid = itemRec1.obfuscated1_uid;
                commit;
            end loop;
            commit;
        end if;
    end loop;

    dbms_output.put_line('Total record read: ' || processCount);
exception
    when others then
        dbms_output.put_line('ORA' || sqlcode);
        dbms_output.put_line(substr(sqlerrm,1,255));
        dbms_output.put_line('ORA- Error during processing ' );
    end;
/
exit;