Hello Sathish
Checksum that is shown in the OSPF database is the checksum that belongs to the specific LSA. It is used to ensure the integrity of the OSPF LSAs as they traverse the network. It is a 16-bit value (typically represented in hexadecimal) that is calculated for each LSA using the contents of the LSA itself.
The checksum is calculated by the sending router, and is included within the contents of the LSA itself. When the receiving router processes it, it calculates the checksum again and compares it with the value within the LSA. If they are the same, the LSA is deemed uncorrupted and error-free. If it is not, it is discarded.
This checksum should not be confused with the checksum that is included in all OSPF messages. This checksum ensures the integrity of the entire OSPF message that is transmitted over the network, and exists for all OSPF packets.
I hope this has been helpful!
Laz