C# MYSL Insert query cannot update or add a child row

Question

This is the error i get Cannot add or update a child row:

a foreign key constraint fails (selo.klijent, CONSTRAINT klijent_ibfk_1 FOREIGN KEY (GradID) REFERENCES grad (GradID))

this is my insert query

 string insertQuery = " INSERT INTO selo.Klijent(KlijentID,Ime,Prezime,Adresa,GradID,Telefon,Email,AktivanKlijent) Values('" + TB_Sifra + "','" + TB_Ime.Text + "','" + TB_Prezime.Text + "','" + TB_Adresa.Text + "','" + CB_Gradovi + "','" + TB_Telefon + "','" + TB_Mail.Text + "','" + proveraRB() + "')";

and this is my mysql code

create table Klijent(

KlijentID INT NOT NULL AUTO_INCREMENT primary key,
Ime varchar(20) not null,
Prezime varchar(20) not null,
Adresa varchar(20) not null,
GradID  INT NOT NULL,
Telefon int not null,
Email varchar(20),
AktivanKlijent varchar(2),

FOREIGN KEY (GradID) REFERENCES Grad(GradID)
);

Really not sure what to do here

In your grad table, you must have a record with GradID which you are trying to insert to Klijent table. If you already have it, provide more details. — Doruk, Apr 27 '18 at 06:58
this is gradID from table Grad GradID INT NOT NULL AUTO_INCREMENT, — Ilija Pavlovic, Apr 27 '18 at 07:02

Ole EH Dufour · Answer 1 · 2018-05-10T14:37:42.230

2

You didn't provide an existing GradID. Furthermore you shouldn't pass a KlijentID because that is an autoincrement. Besides, your code can be hacked: better use a parametrized query.

edited May 10 '18 at 14:37

answered Apr 27 '18 at 06:59

Ole EH Dufour

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I provide GradID from CB_Gradovi – Ilija Pavlovic Apr 27 '18 at 07:09
@IlijaPavlovic You are right. I modified my answer accordingly. – Ole EH Dufour Apr 27 '18 at 07:17

score 2 · Answer 2 · answered Apr 27 '18 at 07:00

2

check Grad table - GradID column have the GradID value

PS.you have to know : How does the SQL injection from the “Bobby Tables” XKCD comic work?

answered Apr 27 '18 at 07:00

Wei Lin

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score 0 · Accepted Answer · answered Apr 30 '18 at 19:58

0

I didnt convert CB value to int.

answered Apr 30 '18 at 19:58

Ilija Pavlovic

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2

C# MYSL Insert query cannot update or add a child row

3 Answers3