Thank you Mark, As per your suggestions yesterdayu to delete the cdx file of ocdata.dbf i did and then tried to open the table exclusively and still the number of records in it are same 4624.
When tried to open the ocdata.dbf it gave a message saying the cdx file is missing, i said ignore and then open i see still 4624 records only in it.
Do you think the .fpt and .dbf are corrupted.
And the table ocdata.fpt size is 298 MB

If .fpt file is corrupted is there any chance for me to bring back those 300,000 records from it.

I did another test by packing the table, the size went down from 298MB to 6MB and then the table started working perfectly. but the records are lost, this i did on the another backup file.

Please give me your suggestions.

Thank you.