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Systems Analysis and Design. Entity Life Histories. (SSADM) Data Views. System Data. Function. Structure. DFD. LDS. Sequence. ELH. Sequence. Entity Name. Event C. Event A. Event B. Selection. Employee. Event D. New Employee. Event E. New Staff Recruited. New Trainee Accepted.
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Systems Analysis and Design Entity Life Histories
(SSADM) Data Views System Data Function Structure DFD LDS Sequence ELH
Sequence Entity Name Event C Event A Event B
Selection Employee Event D New Employee Event E New Staff Recruited New Trainee Accepted
Iteration Employee Employee Life New Employee Event E Salary Payment
Bank Account Entity Bank Account Account Deletion Account Opened Account Closure Account Life Transaction Pay Deposit Direct Deposit Cheque Cashed
Employee Entity Employee Main Life New Employee Possible Ends New Trainee Accepted Salary Payment Employee Resigns Employee Fired New Staff Recruited
State Indicators Entity Account Life Account Closure Account Deletion Birth Event -/1 1/2 2/3 3/- State Indicator Format: valid previous values/value set by event
Bank Account Entity Bank Account Account Deletion Account Opened Account Closure Account Life -/1 1,2,3,4/5 5/- Transaction Pay Deposit Direct Deposit Cheque Cashed 1,2,3,4/2 1,2,3,4/3 1,2,3,4/4
Bank Account Entity Bank Account Account Deletion Account Opened Account Closure Account Life -/1 1,2,3,4/5 5/- 1 5 6 Transaction • Operations List • Create record with account details • Add transaction amount to current balance – code a • Add transaction amount to current balance – code b • Subtract transaction amount from current balance • Replace account status by ‘N’ • Delete account record Pay Deposit Direct Deposit Cheque Cashed 1,2,3,4/2 1,2,3,4/3 1,2,3,4/4 2 3 4
Following the opening of a bank account, a number of transactions may occur. These can be a deposit over the counter, a transfer from another account or a cheque withdrawal. The account must be closed before it can be deleted. Draw an entity life history (ELH) diagram to reflect the above sequence of events. Include status indicators and an operations list.
ENTITY – EVENT MATRIX Order > 12 months old Order Received Payment Received Goods Despatched etc … Create Order Delete Modify Customer Modify Create Invoice Create Payment etc …