Before any changes to database structure are attempted one should first:
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.
Answer: Option D
This Question Belongs to Database >> Database Redesign
Which of the following SQL statements are helpful in database redesign?
A. Correlated subqueries only
B. EXISTS/NOT EXISTS expressions only
C. Both of the above are helpful
D. None of the above are helpful
What SQL command can be used to delete columns from a table?
A. MODIFY TABLE TableName DROP COLUMN ColumnName
B. MODIFY TABLE TableName DROP ColumnName
C. ALTER TABLE TableName DROP COLUMN ColumnName
D. ALTER TABLE TableName DROP ColumnName
Database redesign is not terribly difficult if the:
A. database is structured.
B. database is well-designed.
C. database has no data.
D. database is relatively small.
Which SQL-92 standard SQL command can be used to change a table name?
A. RENAME TABLE
B. CHANGE TABLE
C. ALTER TABLE
D. None of the above is correct
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