Question 1

Forgetting to mark primary and foreign keys, with asterisks or underlining, at every stage of decomposing a relation into 2NF and 3NF.

Accepted Answer

Re-mark every key at every step of the normalisation, even for a table that looks unchanged from the previous stage. Losing the key markers loses marks separately from getting the normal form itself right.

Question 2

Writing SQL CHECK constraints with incorrect syntax, for example omitting the equality operator when checking that a delivery date is on or after an order date.

Accepted Answer

Write comparison operators out fully, greater than or equal to, not just greater than, when a business rule allows the two dates to match.

Question 3

Using an inner join to find parent records with no matching child rows, which silently excludes exactly the records the question is asking for.

Accepted Answer

Use a LEFT JOIN from the parent table and add a WHERE clause checking that the child table's key IS NULL to isolate unmatched parent rows.

Question 4

Miscalculating a PERT backward pass when more than one successor activity converges on the same predecessor, by using the wrong one of the competing late start times.

Accepted Answer

When several activities depend on the same predecessor, its late finish time is the smallest of their late start times, not the largest. Work backward one node at a time and write each value down.

Question 5

Writing a generic, textbook-style answer to a quality of written communication question, such as Agile versus Waterfall or a feasibility study, without linking it to the pre-release case study.

Accepted Answer

Name the business and the specific characters or business rule from the case study in your opening sentence, and keep referring back to them through the answer.

Question 6

Leaving non-aggregate attributes out of the GROUP BY clause when writing an SQL query that sums or counts values across a joined table.

Accepted Answer

List every selected column that is not inside an aggregate function in the GROUP BY clause, and use COUNT(DISTINCT ...) if a join could produce duplicate rows for the same entity.

Question 7

Confusing extreme test data, valid values at the edge of an acceptable range, with erroneous test data, values of the wrong type or outside the range entirely.

Accepted Answer

Keep the two categories separate in a test plan: extreme data should be accepted by the system, erroneous data should be rejected. State the expected outcome for each row.

Question 8

Getting the argument order wrong in SQL date functions such as DATEDIFF or DATEADD, which reverses the sign of the result.

Accepted Answer

Check the specific date function's parameter order before the exam and write it from memory correctly, start date and end date are not interchangeable in DATEDIFF.

Software Systems Development CL4 เคล็ดลับการสอบ

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โปรแกรมเครื่องคิดเลข

PERT forward and backward pass running totals

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