ICT in Data Management
Processing of Sequential
1.3.
Changing
a New
Modifying
Record a Record
2.Addind
Deleting
a /Record
Files
- Master and Transaction files are run together
- - Keyfields
of both
are compared
Masterand
and
Transaction
filesare
arerun
runtogether
together
- Master
Transaction
files
- - The
lower keyfied
is written on new master file
Keyfields
are compared
- Match
is found
-- Process
continues
till is
theignored
end is reached
The onewith
to
be
deleted
- Record
new
details
in transaction file is written instead
- Next field is written on new master file
Records are stored in order eg. by surname on disk for
direct access.
•
Each record has a fixed size.
•
Index table shows where on disk record is stored eg. 1 to 26
(A to Z) ;1=A records, 2=B records………
•
Example: To read a record starting with “S”, all records from
“A” to “R” are ignored. All from “S” have then to be gone
through . This allows faster access eg. batch processing of
employee records.