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- Question
Changing cardinalities in a database is:
Options- A. a common database design task.
- B. a rare database design task, but does occur.
- C. a database design task that never occurs.
- D. is impossible to do, so a new database must be constructed and the data moved into it.
- Correct Answer
- a common database design task.
- 1. How many copies of the database schema are typically used in the redesign process?
Options- A. One
- B. Two
- C. Three
- D. Four Discuss
- 2. Before any changes to database structure are attempted one should first:
Options- A. clearly understand the current structure and contents of the database only.
- B. test any changes on a test database only.
- C. create a complete backup of the operational database only.
- D. All of the above should be done. Discuss
- 3. To drop a column that is used as a foreign key, first:
Options- A. drop the primary key.
- B. drop the table containing the foreign key..
- C. drop the foreign key constraint.
- D. All of the above must be done. Discuss
- 4. Which SQL-92 standard SQL command can be used to change a table name?
Options- A. RENAME TABLE
- B. CHANGE TABLE
- C. ALTER TABLE
- D. None of the above is correct. Discuss
- 5. The EXISTS keyword will be true if:
Options- A. any row in the subquery meets the condition only.
- B. all rows in the subquery fail the condition only.
- C. both of these two conditions are met.
- D. neither of these two conditions is met. Discuss
- 6. Which is not true of a correlated subquery?
Options- A. EXISTS/NOT EXISTS is a form of a correlated subquery.
- B. The processing of the SELECT statements is nested.
- C. They can be used to verify functional dependencies.
- D. They are very similar to a regular subquery. Discuss
- 7. The process of reading a database schema and producing a data model from that schema is known as:
Options- A. data modeling.
- B. database design.
- C. reverse engineering.
- D. None of the above is correct. Discuss
- 8. Because of the importance of making data model changes correctly, many professionals are ________ about using an automated process for database redesign.
Options- A. optimistic
- B. skeptical
- C. ambivalent
- D. None of the above is correct. Discuss
- 9. Which of the following modifications may not succeed?
Options- A. Changing a column data type from char to date
- B. Changing a column data type from numeric to char
- C. Both of the above actions should succeed.
- D. Neither of the above actions will succeed. Discuss
- 10. What SQL command will allow you to change the table STUDENT to add the constraint named GradeCheck that states that the values of the Grade column must be greater than 0?
Options- A. ALTER TABLE STUDENT ALTER CONSTRAINT GradeCheck (Grade > 0);
- B. ALTER TABLE STUDENT ADD CONSTRAINT GradeCheck (Grade > 0);
- C. ALTER TABLE STUDENT ADD CONSTRAINT GradeCheck CHECK (Grade > 0);
- D. None of the above is correct. Discuss
Database Redesign problems
Search Results
Correct Answer: Three
Correct Answer: All of the above should be done.
Correct Answer: drop the foreign key constraint.
Correct Answer: None of the above is correct.
Correct Answer: any row in the subquery meets the condition only.
Correct Answer: They are very similar to a regular subquery.
Correct Answer: reverse engineering.
Correct Answer: skeptical
Correct Answer: Changing a column data type from char to date
Correct Answer: ALTER TABLE STUDENT ADD CONSTRAINT GradeCheck CHECK (Grade > 0);
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