in datagridview how clear previous record and updated the new records using csharp

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C#

for this week Monday to Friday i save all the records in the data base.records as follows in data grid view.
see the below records in data grid view.this record i saved in the database.

Date Session CK Mk RK GK GS NR UNNI MK NR PN

28 Jan 1 REO
28 Jan 2 TASCO
28 Jan 3 PH2
28 Jan 4 AFF
29 Jan 1 TFC
29 Jan 2 MFA
29 Jan 3 CTF
29 Jan 4 LGTF
30 Jan 1 CTF
30 Jan 2 MFA
30 Jan 3 PH2
30 Jan 4 MFA
31 Jan 1 ECDIS
31 Jan 2 ERSM
31 Jan 3 ARPA
31 Jan 4 ERSM
01 Feb 1 ARPA
01 Feb 2 ARPA
01 Feb 3 ECDIS
01 Feb 4 LGTF
02 Feb 1 ECDIS
02 Feb 2 ERSM
02 Feb 3 ARPA
02 Feb 4 ERSM

in the next week monday to friday i save all the records in the database.
when i save the previous record(the above record) i saved that record to be deleted and save the updated record in the data base.

how can i do.please help me.