Hi Vijaya,
You can also store your string in parts in a table where each part is a size which is allowable by your system.
One of the ways in which I have done something similar to your requirement is save comments in 1002 info type. This info type stores long comments in parts. It basically has the provision of dividing a large string into small parts which linked together.
You can try something similar to this. There are some function modules which can help you achieve this.
Regards,
Karan