Database - Database Redesign

Database - Database Redesign
1.  Which of the following SQL statements are helpful in database redesign?
  • Correlated subqueries only
  • EXISTS/NOT EXISTS expressions only
  • Both of the above are helpful
  • None of the above are helpful.
Show Answer
2. What SQL command can be used to delete columns from a table?
  • MODIFY TABLE TableName DROP COLUMN ColumnName
  • MODIFY TABLE TableName DROP ColumnName
  • ALTER TABLE TableName DROP COLUMN ColumnName
  • ALTER TABLE TableName DROP ColumnName
Show Answer
3. Database redesign is not terribly difficult if the:
  • database is structured.
  • database is well-designed.
  • database has no data.
  • database is relatively small.
Show Answer
4. Which SQL-92 standard SQL command can be used to change a table name?
  • RENAME TABLE
  • CHANGE TABLE
  • ALTER TABLE
  • None of the above is correct.
Show Answer
5. The process of reading a database schema and producing a data model from that schema is known as:
  • data modeling.
  • database design.
  • reverse engineering.
  • None of the above is correct.
Show Answer
6. Before any changes to database structure are attempted one should first:
  • clearly understand the current structure and contents of the database only.
  • test any changes on a test database only.
  • create a complete backup of the operational database only.
  • All of the above should be done.
Show Answer
7. Which of the following modifications may not succeed?
  • Changing a column data type from char to date
  • Changing a column data type from numeric to char
  • Both of the above actions should succeed.
  • Neither of the above actions will succeed.
Show Answer
8. How can you find rows that do not match some specified condition?
  • EXISTS
  • Double use of NOT EXISTS
  • NOT EXISTS
  • None of the above is correct.
Show Answer
9. A regular subquery can be processed:
  • from the top down.
  • from the bottom up.
  • by nesting.
  • None of the above is correct.
Show Answer
10. What SQL command can be used to add columns to a table?
  • MODIFY TABLE TableName ADD COLUMN ColumnName
  • MODIFY TABLE TableName ADD ColumnName
  • ALTER TABLE TableName ADD COLUMN ColumnName
  • ALTER TABLE TableName ADD ColumnName
Show Answer
Database
Questions and Answers for Competitive Exams Various Entrance Test