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New way to fix BUG#19243 "wrong LAST_INSERT_ID() after ON DUPLICATE KEY UPDATE".

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This bug report was two problems:
1) LAST_INSERT_ID() returns a value which does not exist in the table
2) the reporter would want it to return the autoinc id of the updated
row.
1) is a real bug, 2) is a feature request.
In July I implemented 2) in 5.1 (which automatically fixes 1).
This has not yet been documented or released, so is changeable.
Precisely, recently Paul and a user found an easy workaround to give
2), which works in 4.1-5.0-5.1. So I can revert my code for 2),
because it's not needed, that's what I do here;
we forget about 2) (we will document the workaround).
But when I revert my code for 2), 1) comes back. We solve 1) by saying
that if INSERT ON DUPLICATE KEY UPDATE updates a row, it's like a
regular UPDATE: LAST_INSERT_ID() should not be affected (instead of
returning a non-existent value).
So note: no behaviour change compared to the last released 5.1; just
a bugfix for 1).


mysql-test/r/innodb_mysql.result:
  result update
mysql-test/t/innodb_mysql.test:
      test for the new way to fix BUG#19243: that if INSERT ON DUPLICATE
      KEY UPDATE updates a row, SELECT LAST_INSERT_ID() is not affected.
      Test of the workaround for people who want SELECT LAST_INSERT_ID()
      to return the autoinc id of the updated row.
sql/sql_insert.cc:
  No need to change LAST_INSERT_ID() if INSERT ON DUPLICATE KEY UPDATE
  updates a row, there is a workaround to achieve this without changing
  code: just add "autoinc_col=LAST_INSERT_ID(autoinc_col)" to your
  ON DUPLICATE KEY UPDATE clause.
  Prevent LAST_INSERT_ID() to contain an inexistent value in this case:
  if the row is updated it should be like a regular UPDATE: don't
  affect LAST_INSERT_ID() (achieved by marking that we didn't generate
  an id for this row: insert_id_for_cur_row=0).
This commit is contained in:
unknown
2006-09-06 12:50:42 +02:00
parent 601a2df05b
commit c3cef377fe
3 changed files with 51 additions and 15 deletions
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21
mysql-test/t/innodb_mysql.test
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@@ -369,8 +369,8 @@ insert into t1 values('aaa');
drop table t1;
# Fix for BUG#19243 "wrong LAST_INSERT_ID() after ON DUPLICATE KEY
# UPDATE": now LAST_INSERT_ID() will return the id of the updated
# row.
# UPDATE": if the row is updated, it's like a regular UPDATE:
# LAST_INSERT_ID() is not affected.
CREATE TABLE `t2` (
`k` int(11) NOT NULL auto_increment,
`a` int(11) default NULL,
@@ -390,6 +390,12 @@ insert into t2 ( a ) values ( 6 ) on duplicate key update c =
ifnull( c,
0 ) + 1;
select last_insert_id();
# test again when last_insert_id() is 0 initially
select last_insert_id(0);
insert into t2 ( a ) values ( 6 ) on duplicate key update c =
ifnull( c,
0 ) + 1;
select last_insert_id();
select * from t2;
# Test of LAST_INSERT_ID() when autogenerated will fail:
@@ -402,5 +408,14 @@ insert ignore into t2 values (null,6,1),(null,8,1),(null,15,1),(null,20,1);
select last_insert_id();
select * from t2;
drop table t2;
# Test of the workaround which enables people to know the id of the
# updated row in INSERT ON DUPLICATE KEY UPDATE, by using
# LAST_INSERT_ID(autoinc_col) in the UPDATE clause.
insert into t2 ( a ) values ( 6 ) on duplicate key update c =
ifnull( c,
0 ) + 1, k=last_insert_id(k);
select last_insert_id();
select * from t2;
drop table t2;