Why foreign key column allowing null values even a parent
tables reference key column not having null value..
Answers were Sorted based on User's Feedback
Answer / rajkumar
Foreign key consider only the values. According to null value is not a value.
| Is This Answer Correct ? | 1 Yes | 0 No |
Answer / sureshramsing@gmail.com
Yes foreign key column allows null values, if it is not having either primary key or not null constraints.
Foreign key just reference to the particular parent column only not for restrcting the data while insert or update. It verifies dependency at the time of delete only.
| Is This Answer Correct ? | 1 Yes | 1 No |
What is difference between stored procedure and user defined function?
Hi All, I want to display all duplicate records in the table. My query has to fetch all the records which are duplicate(First Name or Last Name). Also I want the ability to also pull names where there might be a middle initial placed in the end of the first name field, (i.e., "Maria Z. " vs. "Maria") as well. Please guide me to find this. Table: ID FirstName LastName 1 Zach H Hoffman 2 Zach Hoffman 3 Troy Hoffman 4 Shawn Livermore 5 Prem S 6 Jony Hoffman H 7 Zach Modan I need the query to filter......... ID FirstName LastName 1 Zach H Hoffman 2 Zach Hoffman 3 Troy Hoffman 6 Jony Hoffman H 7 Zach Modan I hope this example will give you clear idea..... Thanks in Advance Prem
What is difference between temp table and cte?
when would you go for denormalization? : Sql server database administration
what are the basic functions for master, msdb, model, tempdb and resource system databases? : sql server database administration
What is sql stored procedure?
What is a non clustered primary key?
What is normalization? Describe its different types.
How to provide values to user defined function parameters?
What is difference between view and materialized view?
Can you explain what is sql server english query?
When to use Inner join & when to use subquery?
Oracle (3259)
SQL Server (4518)
MS Access (429)
MySQL (1402)
Postgre (483)
Sybase (267)
DB Architecture (141)
DB Administration (291)
DB Development (113)
SQL PLSQL (3330)
MongoDB (502)
IBM Informix (50)
Neo4j (82)
InfluxDB (0)
Apache CouchDB (44)
Firebird (5)
Database Management (1411)
Databases AllOther (288)