How can I get the unique ID for the last inserted row?

If you insert a record that has a AUTO_INCREMENT index then you can get the given id with mysql_insert_id(MYSQL *).

The last value is also stored in the server and can be retrieved with the LAST_INSERT_ID() function.

You can check if an auto_increment index is used by the following code. This also checks if the query was an INSERT with an auto_increment index.

if (mysql_error(MYSQL)[0] == 0 &&
    mysql_num_fields(MYSQL_RESULT) == 0 &&
    mysql_insert_id(MYSQL) != 0)
  used_id = mysql_insert_id(MYSQL);

The id that LAST_INSERT_ID() returns is maintained in the server per connection. It will not be botched by another client. It will not even be changed if you update another auto_increment column with a non magic value (that is a not NULL or 0).

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