Question

In an Oracle table (e.g. MYTABLE, with a numeric sequenced field as primary key), I have to insert several thousand of rows, but some of them are supposed to already exist in the table.

Naturally, I should try to use MERGE but I need, as well, to retrieve all created (when inserting) and existing (when updating) primary keys.

As well, it should be as fast as possible.

Is the following attempt (pseudo code) the only way to go? Thanks.

keys_list = empty array
for each row to merge
    do query 'SELECT PK_MYTABLE FROM MYTABLE WHERE PK_MYTABLE = '+row.pk_mytable
        ==> retrieve key
    if found then:
        add key to keys_list
    else:
        do query 'INSERT INTO MYTABLE (PK_MYTABLE, ...) VALUES (SEQ_MYTABLE.NEXTVAL, ...)'
        do query 'SELECT SEQ_MYTABLE.CURRVAL FROM DUAL' ==> retrieve key
        add key to keys_list

Answer 1

Add a MODIFICATION_DATE column to the table

Grab and save the sysdate.

When you merge update/insert the value of the sysdate as well.

When the merge is complete, select the rows where the MODIFICATION_DATE = SYSDATE and you
have the set you are interested in.