ERROR Cannot add or update a child row a foreign key constraint fails

+1 vote

I have created tables in MySQL Workbench as shown below :

ORDRE table:

CREATE TABLE Ordre (
  OrdreID   INT NOT NULL,
  OrdreDato DATE DEFAULT NULL,
  KundeID   INT  DEFAULT NULL,
  CONSTRAINT Ordre_pk PRIMARY KEY (OrdreID),
  CONSTRAINT Ordre_fk FOREIGN KEY (KundeID) REFERENCES Kunde (KundeID)
)
  ENGINE = InnoDB;

PRODUKT table:

CREATE TABLE Produkt (
  ProduktID          INT NOT NULL,
  ProduktBeskrivelse VARCHAR(100) DEFAULT NULL,
  ProduktFarge       VARCHAR(20)  DEFAULT NULL,
  Enhetpris          INT          DEFAULT NULL,
  CONSTRAINT Produkt_pk PRIMARY KEY (ProduktID)
)
  ENGINE = InnoDB;

and ORDRELINJE table:

CREATE TABLE Ordrelinje (
  Ordre         INT NOT NULL,
  Produkt       INT NOT NULL,
  AntallBestilt INT DEFAULT NULL,
  CONSTRAINT Ordrelinje_pk PRIMARY KEY (Ordre, Produkt),
  CONSTRAINT Ordrelinje_fk FOREIGN KEY (Ordre) REFERENCES Ordre (OrdreID),
  CONSTRAINT Ordrelinje_fk1 FOREIGN KEY (Produkt) REFERENCES Produkt (ProduktID)
)
  ENGINE = InnoDB;

so when I try to insert values into ORDRELINJE table i get:

Error Code: 1452. Cannot add or update a child row: a foreign key constraint fails (srdjank.Ordrelinje, CONSTRAINT Ordrelinje_fk FOREIGN KEY (Ordre) REFERENCES Ordre (OrdreID))

How to fix it?

Aug 20, 2020 in PHP by kartik
• 37,510 points
7,359 views

1 answer to this question.

0 votes

Hello @kartik,

You are getting this constraint check because Ordre table does not have reference OrdreID provided in insert command.

To insert value in Ordrelinje, you first have to enter value in Ordre table and use same OrdreID in Orderlinje table.

Or you can remove not null constraint and insert a NULL value in it.

Hope it helps!!
Thank you!!

answered Aug 20, 2020 by Niroj
• 82,720 points

Related Questions In PHP

0 votes
2 answers

Define a SQL query? What is the difference between SELECT and UPDATE Query? How do you use SQL in SAS?

HI.. SQL is Structured Query Language, which is ...READ MORE

answered Aug 8, 2020 in PHP by anonymous
2,330 views
0 votes
1 answer

Error:PDOException SQLSTATE[HY000] [2020] No such file or directory in php?

Hello, I checked php -i | grep pdo and noticed ...READ MORE

answered Apr 2, 2020 in PHP by Niroj
• 82,720 points
340 views
0 votes
1 answer

Error:Jquery - Uncaught TypeError: Cannot use 'in' operator to search for '324' in

Hello @kartik, You have a JSON string, not ...READ MORE

answered Jun 16, 2020 in PHP by Niroj
• 82,720 points
1,860 views
0 votes
1 answer

How do I UPDATE from a SELECT in SQL Server?

Hello @kartik, In SQL Server, use MERGE MERGE INTO YourTable ...READ MORE

answered Jul 21, 2020 in PHP by Niroj
• 82,720 points
163 views
+1 vote
1 answer

How to make anchor tag with routing using Laravel?

Hey @kartik, First you have to go to ...READ MORE

answered Mar 18, 2020 in Laravel by Niroj
• 82,720 points
7,100 views
0 votes
1 answer

What is redirection in Laravel?

Named route is used to give specific ...READ MORE

answered Mar 18, 2020 in Laravel by Niroj
• 82,720 points
812 views
0 votes
1 answer

How to install Laravel via composer?

Hello, This is simple you just need to ...READ MORE

answered Mar 23, 2020 in Laravel by Niroj
• 82,720 points
629 views
+1 vote
1 answer

What are named routes in Laravel and How can specify route names for controller actions?

Hey @kartik, Named routing is another amazing feature of ...READ MORE

answered Mar 23, 2020 in Laravel by Niroj
• 82,720 points
7,511 views
0 votes
2 answers

Error:“Cannot Connect to Server - A network-related or instance-specific error”?

Hello, The "sql server error 40" is appears mostly ...READ MORE

answered Aug 18, 2020 in PHP by Fantazma
• 140 points
2,201 views