Database Redesign - General Questions Online Exam Quiz
Database Redesign - General Questions GK Quiz. Question and Answers related to Database Redesign - General Questions. MCQ (Multiple Choice Questions with answers about Database Redesign - General Questions
Which of the following SQL statements are helpful in database redesign?
Options
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?
Options
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:
Options
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?
Options
A : RENAME TABLE
B : CHANGE TABLE
C : ALTER TABLE
D : None of the above is correct.
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.
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.
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.
How can you find rows that do not match some specified condition?
Options
A : EXISTS
B : Double use of NOT EXISTS
C : NOT EXISTS
D : None of the above is correct.
A regular subquery can be processed:
Options
A : from the top down.
B : from the bottom up.
C : by nesting.
D : None of the above is correct.
What SQL command can be used to add columns to a table?
Options
A : MODIFY TABLE TableName ADD COLUMN ColumnName
B : MODIFY TABLE TableName ADD ColumnName
C : ALTER TABLE TableName ADD COLUMN ColumnName
D : ALTER TABLE TableName ADD ColumnName
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