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- Question
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.
- Correct Answer
- Changing a column data type from char to date
- 1. 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
- 2. 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
- 3. 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
- 4. 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. Discuss
- 5. How many copies of the database schema are typically used in the redesign process?
Options- A. One
- B. Two
- C. Three
- D. Four Discuss
- 6. 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
- 7. Database redesign is not terribly difficult if the:
Options- A. database is structured.
- B. database is well-designed.
- C. database has no data.
- D. database is relatively small. Discuss
- 8. After a table has been created, its structure can be modified using the SQL command:
Options- A. UPDATE TABLE [TableName].
- B. MODIFY TABLE [TableName].
- C. ALTER TABLE [TableName].
- D. CHANGE TABLE [TableName]. Discuss
- 9. What Oracle backup and recover file contains user and system data?
Options- A. Control file
- B. Datafile
- C. OnLine ReDo file
- D. Offline ReDo file Discuss
- 10. Which statement about sequences is not true?
Options- A. A sequence is an object that generates a sequential series of unique numbers.
- B. Sequences are most often used to provide values for surrogate keys.
- C. NextVal and CurrVal are both sequence methods.
- D. Sequences guarantee valid surrogate key values. Discuss
Database Redesign problems
Search Results
Correct Answer: skeptical
Correct Answer: reverse engineering.
Correct Answer: They are very similar to a regular subquery.
Correct Answer: a common database design task.
Correct Answer: Three
Correct Answer: ALTER TABLE STUDENT ADD CONSTRAINT GradeCheck CHECK (Grade > 0);
Correct Answer: database has no data.
Correct Answer: ALTER TABLE [TableName].
Correct Answer: Datafile
Correct Answer: Sequences guarantee valid surrogate key values.
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