4 3 8 Minimizing Database I Os

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4.3.8 Minimizing Database I/Os

4.3.8.1 Initial Example

4.3.8.2 First Improved Example

4.3.8.3 Second Improved Example

Files Involved

Physical file TRANS (transactions file) has the following fields:

Field	Type	Length	Description
TRANNUM	S	5	Transaction number
TRANTIME	S	6	Transaction time
TRANDATE	S	6	Transaction date
TRANTYPE	A	2	Transaction type
TRANUSER	A	10	Transaction user
TRANSTATE	A	3	Transaction state

and a file called TRNTYP (transaction types/descriptions) has the following fields:

Field	Type	Length	Description
TRANTYPE	A	2	Transaction type
TRANDESC	A	20	Transaction full description

and a file called STATES (state codes/descriptions) has the following fields:

Field	Type	Length	Description
STATCODE	A	3	State code
STATDESC	A	20	State full description