Oracle Equivalent to MySQL INSERT IGNORE?

Question

I need to update a query so that it checks that a duplicate entry does not exist before insertion. In MySQL I can just use INSERT IGNORE so that if a duplicate record is fo

Answer 1

A simple solution

insert into t1
  select from t2 
  where not exists 
    (select 1 from t1 where t1.id= t2.id)

Answer 2

If you're on 11g you can use the hint IGNORE_ROW_ON_DUPKEY_INDEX:

SQL> create table my_table(a number, constraint my_table_pk primary key (a));

Table created.

SQL> insert /*+ ignore_row_on_dupkey_index(my_table, my_table_pk) */
  2  into my_table
  3  select 1 from dual
  4  union all
  5  select 1 from dual;

1 row created.

Answer 3

I don't think there is but to save time you can attempt the insert and ignore the inevitable error:

begin

   insert into table_a( col1, col2, col3 )
   values ( 1, 2, 3 );

   exception when dup_val_on_index then 
      null;

end;
/

This will only ignore exceptions raised specifically by duplicate primary key or unique key constraints; everything else will be raised as normal.

If you don't want to do this then you have to select from the table first, which isn't really that efficient.

Answer 4

yet another "where not exists"-variant using dual...

insert into t1(id, unique_name)
  select t1_seq.nextval, 'Franz-Xaver' from dual 
    where not exists (select 1 from t1 where unique_name = 'Franz-Xaver');

Answer 5

How about simply adding an index with whatever fields you need to check for dupes on and say it must be unique? Saves a read check.

Answer 6

This one isn't mine, but came in really handy when using sqlloader:

1. create a view that points to your table:

   CREATE OR REPLACE VIEW test_view
   AS SELECT * FROM test_tab
   

2. create the trigger:

   CREATE OR REPLACE TRIGGER test_trig
    INSTEAD OF INSERT ON test_view
    FOR EACH ROW
     BEGIN
      INSERT INTO test_tab VALUES
       (:NEW.id, :NEW.name);
     EXCEPTION
      WHEN DUP_VAL_ON_INDEX THEN NULL;
     END test_trig;
   

3. and in the ctl file, insert into the view instead:

   OPTIONS(ERRORS=0)
   LOAD DATA
   INFILE 'file_with_duplicates.csv'
   INTO TABLE test_view
   FIELDS TERMINATED BY ','
   (id, field1)