SQL tutorial 19: ON DELETE SET NULL clause of Foreign Key By Manish Sharma (RebellionRider)

SQL Tutorial 19 : ON DELETE SET NULL foreign key Clause.
Links used in the tutorial

On delete set null website article [ download SQL script from same link] :

This video is the part of foreign key video In this sql tutorial you will learn the referential clause ON DELETE SET NULL of foreign key.
On Delete Set null clause guarantee the relation integrity in foreign key/

Tool used in this tutorial is SQL Developer.
This tutorial series is part of SQL expert exam certification training. if you are preparing for SQL certification you can use my tutorials. This SQL Tutorial is a part of free training.

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[premkumarinti]

i should thank you for this video, i had a confusion about this after watching clearly knew about you manish

[abdullahsaad]

really good job and great job
its help me a lot to learn SQL thank you very mush Mr.Manish

[sanoberjahanansari]

doing a god job, really your videos are awesome
it helps me a lot to learn SQL .

[mohammadhannan]

really  nice and educational vedio.Many Many  thanks.I pray for you .

[mingx]

Nice lectures. Appreciate your great work. Thanks, man.

[NicolaeCristian]

very good tutorial man. Thanks to share to us your knowledge.

[jyotimoi]

The video tutorials are great !!! Thanks a lot #Manish .!!!

[nupursingh]

Very good videos. Getting a thorough understanding of concepts. You should think of creating tutorial videos for websites like Udemy. Its just a suggestion as you will get wider student audience. Best Of luck!!

[babakelikaee]

tnx Manish. you are doing great. I need to add a comment I think drop foreign key and re-create it missed.
ALTER TABLE books DROP CONSTRAINT bok_col3_fk; -- drop foreign key
ALTER TABLE books ADD CONSTRAINT bok_col3_fk FOREIGN KEY (book_author_id) REFERENCES authors(author_id) ON DELETE SET NULL;

[HLDENSUX]

Thanks for this tutorial Manish. I was wondering if you can set another value like Nil instead of Null when deleting a foreign key? The reason I ask is because in database at work, when I remove a relationship between some object tables, the business rule states that I need to remove the applicability of that object, where an applicability of that object can be more than 1 variable across multiple rows. In that situation where the primary key in a parent table existing in the children table more than once as shown by the multiple rows, is there a way to set the delete to Nil to change the objects applicability?

[puneethmohana]

I have added constraints in child table n I can see in GUI in constraint tab. But when I run query for ' user constraint' defined I get 0 value.

[abhrajitghosh]

Qq. instead of dropping the table books, cant we just drop the foreign key constraint? And then add it back using alter table statement?

[basu]

Hi Manish, Thanks for your tutorials.
I have a question, why am i not able to see any data under user_constraints table, any idea. I created Child table under HR schema and when i run user_constraints no data is returned.

[feeltheinnoscence]

hello manish,


after installing the oracle 11g it worked fine. next day when i tried, i am getting this issue.

please help me to fix this.

thankyou in advance.

[multitelentworksshivanipatelzz]

sir plese ap ap ke videohindi me upload karte to hindi ya gujrati media valo ko bhi acha hota

[sriramtorvi]

what if the child table column was set to not null?

[MrManoranjansethy]

Diference Between & and && in SQL WITH example.

[GAVIGHUMMAN]

Your Voice reminds me of "FARHAN AKHTAR"