4. Specify the name of the two problems of the concurrent transactions shown by the figures. Provide a short description

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4 Specify The Name Of The Two Problems Of The Concurrent Transactions Shown By The Figures Provide A Short Description 1 (96.32 KiB) Viewed 4 times

4. Specify the name of the two problems of the concurrent transactions shown by the figures. Provide a short description about each problem. (4 Marks) TIME TRANSACTION STEP STORED VALUE T1 Read PROD_QOH 35 T2 Read PROD_QOH 35 T1 PROD_QOH = 35 + 100 T2 PROD_QOH = 35 - 30 T1 Write PROD_QOH (lost update) 135 T2 Write PROD_QOH 5 TRANSACTION STORED VALUE 35 T1 T1 T1 135 T2 135 T2 T1 35 T2 105 123456 TIME 1945W NE 6 7 Figure A STEP Read PROD_QOH PROD_QOH = 35 + 100 Write PROD_QOH Read PROD_QOH (Read uncommitted data) PROD_QOH = 135 - 30 ***** ROLLBACK ***** Write PROD_QOH Figure B