COMPUTER SCIENCE AND ENGINEERING
SQL
|
Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
|
|
|
PRIMARY KEY
|
|
|
ALTERNATE KEY
|
|
|
FOREIGN KEY
|
|
|
UNIQUE
|
Detailed explanation-1: -A Primary Key can’t be an Alternate Key.
Detailed explanation-2: -1. Which of the following is not a class of constraint in SQL Server? Explanation: NOT NULL specifies that the column does not accept NULL values. For more information.
Detailed explanation-3: -3. Which of the following is not a type of SQL statement? Explanation: Data Communication Language (DCL) is not a type of SQL statement.
Detailed explanation-4: -The NOT NULL constraint enforces a column to NOT accept NULL values. This enforces a field to always contain a value, which means that you cannot insert a new record, or update a record without adding a value to this field.
Detailed explanation-5: -The following constraints are commonly used in SQL: NOT NULL-Ensures that a column cannot have a NULL value. UNIQUE-Ensures that all values in a column are different. PRIMARY KEY-A combination of a NOT NULL and UNIQUE .