Cursor for updating in oracle

Posted by / 21-Jan-2020 19:01

Cursor for updating in oracle

You can circumvent the lock by using the USROPN keyword on the file definition and opening and closing the file as needed, but even in that scenario, if you change the file, the program will get a level-check error the next time it tries to open the file.

SQL Unbound SQL provides a real benefit here because of its unbound nature.

It can also looks like this: select id, a, b from tb_target union all select id, a, b from tb_source Then, we've group records by all columns in this view and counting appearance by primary key (i.e.: id): select id, count(1) cnt group by id, a, b In group clause You must specify all columns, which can be updated/insert, and in counting specify only pk fields.

i just want to insert new records and update the existing records only if they have changed...' My example is a little complicate, but maybe would be helpfull.

One DML instruction - nothing else: /* trg: target table to update/insert into */ merge into tb_target trg using __/* base query with wanted records */ __(select, src2.a, src2.b, cbn2__from tb_source src2, ____/* choosing records for update/insert only */ ____(select, count(1) cnt ____from ______/* combine records of both tables */ ______(select id, count(1) cnt ______from ( ________select * from tb_target ________union all ________select * from tb_source) ______group by id, a, b) cbn, --specify all columns ______tb_source src ____/* cnt=1 : different rec in source table (or not exists in target) */ ____where = and cbn.cnt=1 ____group by cbn2 __where src2= fin /* condition for matches: cnt=2/update; cnt=1/insert */ on (= and = 2) when matched then __update set trg.a=fin.a, trg.b=fin.b when not matched then __insert (,trg.a,trg.b) values (, fin.a, fin.b) /* combine records of both tables */ (select id, count(1) cnt from ( __select * from tb_target __union all __select * from tb_source) group by id, a, b) cbn --specify all columns tb_source - table with records to load tb_target - table with records for update or insert from tb_source Say, we have 3 columns: id, a and b.

Let's say that you have some seq_number as a unique identifier in the table and that also exists as a uniqe identifier in you cursor. Re-Write your original cursor to do this: declare cursor cur_insert is select all from your cursor data a where not exists (select 'x' from your table b where a.seq_number = b.seq_number); --only new records Begin for x in cur_insert loop insert into your_table(columns) values(x.columns); end loop; commit; 2. declare cursor cur_update is select a.* from your_cursor_data a, your_table b where a.seq_number = b.seq_number and (a.column1 b.column2 or......); /* only ones that are different from what is in the table*/ begin for x in cur_update loop update your_table set column1= x.column1, column2 = x.column2......

where seq_number = x.seq_number; end loop; commit; end; This of course can be all combined into one anonymous block or procedure.

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Cheers." id="ctl00_m_m_i_ctl00_gr_ctl01_bestanswerbody" class="textarea-bestanswerhidden" name="bestanswerbody" answerbody Id="2758306" / You need to check new records against existing records for some uniqueness value.