Mysql Foreign Keys

Mysql Foreign Keys

Easy Questions

MYSQL

MySQL Subquery
MySQL Character Set
MySQL Views
Mysql Basic
Mysql Setup
Mysql Foreign Keys
Mysql Query Optimization
Interacting With MySQL
Server SQL Mode
MySQL Events
MySQL UNION
MySQL Full-Text Search
MySQL Command Line Tool
Mysql Error handling
Mysql Compound Statements
MySQL Stored Procedures
MySQL Stored Functions
MySQL Triggers
MySQL Connectors and APIs
Connection
MySQL Functions
MySQL Operators
MySQL Table Operations
MySQL Internationalization and Localization
MySQL Database Operations
MySQL Access Control and Security
MySQL Type Conversion in Expression Evaluation
MySQL Scheduling and Locking Issues
MySQL ORDER BY
MySQL HAVING
MySQL GROUP BY
MySQL Optimization
Managing MySQL Users
MySQL Programs
Access Control for MySQL Stored Programs and Views
Create Database
Drop Database
Select Database
Data Types
Create Tables
Insert Query
Select Query
Mysql miscellaneous
Where Clause
Update Query
Delete Query
Sorting Results
Using Join
NULL Values
Transactions
Alter Command
Indexes
Database Info
Using Sequences
  1. Which clause in the SQL standard controls how NULL values in a composite foreign key are handled when comparing to a primary key.










  1. View Hint View Answer Discuss in Forum

    NA

    Correct Option: D

    The MATCH clause in the SQL standard controls how NULL values in a composite (multiple-column) foreign key are handled when comparing to a primary key. MySQL essentially implements the semantics defined by MATCH SIMPLE.

  1. Which keyword is used to specify the foreign key after the table is created?










  1. View Hint View Answer Discuss in Forum

    NA

    Correct Option: B

    When the table has already been created but the foreign key has not been set of foreign key constraints are not specified, the ‘ALTER TABLE – ADD FOREIGN KEY’ clause is used.

  1. Which clause is used to remove a foreign key constraint?










  1. View Hint View Answer Discuss in Forum

    NA

    Correct Option: B

    In MySQL foreign key definition syntax, there are various components. A foreign key links one table to another table in the table. To remove a foreign key constraint, the ‘DROP’ clause is used.

  1. If the storage engine InnoDB is not used, foreign key cannot be used.










  1. View Hint View Answer Discuss in Forum

    NA

    Correct Option: B

    The foreign key support is exclusively provided by the storage engine named InnoDB. Without its inclusion, foreign keys cannot be used. However it is possible to implement with application logic.

  1. Which clause names the parent table and the index columns in the table?










  1. View Hint View Answer Discuss in Forum

    NA

    Correct Option: C

    In MySQL foreign key definition syntax, there are various components, namely, FOREIGN KEY, CONSTRAINT, REFERENCES and ON DELETE. The REFERENCES clause names the parent table and the index columns in the table.