Dear Developers, I was doing prototype for this project as Mr Sergei Golubchik suggested "This task is about creating MI_UNIQUEDEF "uniques" instead of MI_KEYDEF "keys" for long unique constraints." Here is my output MariaDB [sachin]> create table tbl(int_key int primary key , blob_key blob unique); Query OK, 0 rows affected (0.03 sec) MariaDB [sachin]> insert into tbl values(1,1); Query OK, 1 row affected (0.01 sec) MariaDB [sachin]> insert into tbl values(2,1); ERROR 1062 (23000): Duplicate entry '1' for key 'blob_key' MariaDB [sachin]> insert into tbl values(2,2); Query OK, 1 row affected (0.00 sec) MariaDB [sachin]> insert into tbl values(3,3); Query OK, 1 row affected (0.00 sec) MariaDB [sachin]> select * from tbl; +---------+----------+ | int_key | blob_key | +---------+----------+ | 1 | 1 | | 2 | 2 | | 3 | 3 | +---------+----------+ 3 rows in set (0.00 sec) I am assuming that unique blob will have 0 zero key . Should i mail you the source code.Please let me know Regards sachin