Which of the following statement is FALSE?
A Primary Key cannot be NULL
A Foreign Key cannot be NULL
A Primary Key cannot be Duplicate
A Foreign Key can be Duplicate
Correct Answer :
B. A Foreign Key cannot be NULL
The option (B) is false, because a foreign key can be NULL or duplicate.
Related Questions
What does the following statement do?
Finds any values that start with a and ends with o
Finds any values whose first character is a and third character is o
Both A. and B.
None of the above
In order to insert a row directly in the table, which command is used?
INSERT IN
INSERT INSIDE
INSERT UNDER
INSERT INTO
If multiple columns are used as Primary Key, it is known as
Unique
Composite
Foreign
None of the above
Select the correct constraint in SQL?
NOT NULL
CHECK
DEFAULT
All of the above
Which of the following statement is correct?
Comparison Operator has higher precedence than Conjuction Operator.
Identity Operator has higher precedence than Multiplication Operator.
Both A and B
None of the above
Rules that are needed to be followed in SET Operators in SQL are
All columns must be identical in number and order.
There must be compatibility between data types.
Both A and B
None of the above
In SQL SELECT COUNT, one needs to specify the
Column Name
Row Name
Table Name
None of the above
In case of ____ data, recursive CTE is used?
Round
Hierarchal
Linear
None of the above
In how many categories data types has been classified?
2
3
4
5
Which of the following is not MySQL Numeric Data Type?
BIT(Size)
CHAR(Size)
INTEGER(Size)
INT(Size)
What is the difference between VARCHAR and VARCHAR2?
VARCHAR can store upto 4000 bytes and VARCHAR2 can store upto 8000 bytes.
VARCHAR can store upto 2000 bytes and VARCHAR2 can store upto 4000 bytes.
Both VARCHAR and VARCHAR2 are similar but use of VARCHAR2 is mostly recommended.
There is no similarity between VARCHAR and VARCHAR2.
To delete table definition and all data from the table, which statement is used?
DELETE
DROP
ALTER
None of the above
Global Temp Variable is used with which sign?
###
####
#
##
Numbers of operand used by Binary Operators are?
1
2
3
4
SQL has the disadvantage of?
SQL is cheap.
SQL interface is simple.
Both A and B.
None of the above.
Which of the following is SQL Server Date and Time Data Type?
timestamp
sql_variant
real
text
The numerical values of two ___ of the ___ table can be easily subtracted using SQL Subtraction Operator.
Rows, same
Columns, same
Rows, different
Columns, different
What does the DELETE Statement do?
A new table in SQL is created using this SQL statement.
By deleting the stored data, this SQL statement deletes the database.
Columns in the SQL database can be created, deleted, or modified with this SQL statement.
By executing this SQL statement, you remove the table and all the information that it contains, including the structure, views, permissions, and triggers.
Select the correct syntax for Multi-line Comments.
//*Line1
Line2*//
/*Line1
Line2/*
Which of the following is not MySQL String Data Type?
TEXT(Size)
TINYTEXT
MEDIUMTEXT
LARGETEXT
How can we prevent SQL Injection attack?
We should pre-define the input type, input field and length of the user data to validate the input for the user authentication.
Access privileges should be restricted for the users
Administrator accounts should not be used.
All of the above
Which of the following is TRUE about TCL?
Transactions can be saved to the database and rolled back with the help of TCL commands in SQL.
There will be certain privileges that each user has; consequently, the data can be accessed by them using TCL.
Our data is stored in a table that is described by the schema, thus TCL commands deal with the schema.
SQL TCL commands can be used to perform any kind of retrieval or manipulation of the data present in SQL tables.
At which of the following stage does SQL Injection occurs?
When the user is asked to logout
When the user is asked to input password
When the user is asked to input captcha
When the user is asked to input username
What does the ROLLBACK Statement do?
Specify the columns of the table in this SQL statement to return distinct values.
Changes made in the SQL database transaction are permanently saved using this SQL statement.
By running this SQL statement, the transaction will be undone and the operations not yet saved to the SQL database will be undone.
An index is created in a SQL database table with this SQL statement.
To add a Primary Key constraint after table is created, which clause is used?
UPDATE
ADD
ALTER
JOIN
____ integrity is achieved by using a foreign key.
Referential Integrity
Domain Integrity
User-defined Integrity
Entity Integrity
What is TRUE about the Active/Dynamic Online Catalog based on the relational model in the 12 Codd's Rules?
The primary key value, table name, and column name are characteristics that allow us to access the precise data (atomic value) logically from a relational database.
Null values are treated in database records according to this rule.
Database dictionaries represent the complete logic of all descriptive data, which must be stored online.
None of the above
Which statement is not true?
SQL is rational whereas No-SQL is non-rational.
SQL follows BASE Model whereas No-SQL follows ACID Model.
SQL database are vertically scalable whereas No-SQL database are horizontally scalable.
No-SQL databases are preferable to store hierarchical data in comparison SQL databases.
Select the correct syntax of SELECT TOP clause?
SELECT TOP name
SELECT TOP column
SELECT TOP FROM
SELECT TOP Number
Which syntax is correct for RENAME DATABASE in MySQL?
RENAME old_database_name TO new_database_name;
RENAME DATABASE old_database_name TO new_database_name;
ALTER old_database_name MODIFY NAME = new_database_name;
ALTER DATABASE old_database_name MODIFY NAME = new_database_name;