EDIT: tables have been translated from my language to english i’ve changed te reference of foreign key in table Comment to “Utente” -> “User” Hi everyone i’m trying to build a small review system in sql as follows. Every user can comment on some item(could be anything) a…
Tag: foreign-keys
ORACLE CREATE TABLE with FOREIGN KEY error
I am a beginner to Oracle and have been having problems creating a table with a foreign key, I have created the parent table region as well and have been receiving the same error. I have researched on W3school and used the same syntax but still no help. Answer Leave “FOREIGN KEY” out, if you want …
How to copy data from one table to another when foreign key is only defined in the destination table?
Table_A schema: Table_B schema: Column UserId is defined as Foreign Key in Table_A. I need to copy data from Table_B to Table_A and I used: But I get: The INSERT statement conflicted with the FOREIGN KEY constraint “FK_UserId” The conflict occurred in database “Table_A”, table “d…
I can not make a composite relationship between 2 tables in SQL Server
I have the next schema where I want to relation the tables COMPANIES_COUNTRIES and TIME_TRACKING_REQUEST_TYPE by CountryId and CompanyId. DB Schema The scripts for both tables are the next: I tried to make a composite relationship with next script but didn’t work: I get this error (sorry, it is in Spani…
id value needs a default value according to error 1364?
I want to create two tables. practice has a AUTO_INCREMENT attachment and is a PRIMARY KEY. continued has the id entity continued_id which exists as a FOREIGN KEY that references practice(user_id). Mysql executes the code below fine until line 19, where I receive the 1364 error, stating that continued_id has …
T-SQL – Adding FK to table, make it do drop/null/efault automagically?
If I had two tables where I need to add a new foreign key to, say: ALTER TABLE [release_user] ADD CONSTRAINT [user_release] FOREIGN KEY ([user_id]) REFERENCES [user_table] ([user_id]) …
Search for and reverse engineer foreign key relationships in DB without foreign keys defined
I’ve inherited a really old database with about 100 tables. I know there are foreign key relationships by looking through tables, but I’ve also determined that there are no relationships actually …
Laravel 5.8 / Mysql: Cannot delete or update a parent row a foreign key constraint fails
I am trying to setup my tables in my MySQL database and and I am currently creating migration files using Laravel 5.8. When I run a fresh migration with php artisan migrate all the migrations run …
SQL JOIN and desired a view: 2 foreign keys referencing the same table
I feel I can’t solve my task without community help. Unfortunately, my knowledge of SQL is weak. I have 2 tables – user and referral which represents data about senders and referral of senders (…
How to avoid adding duplicate foreign key constraints
I would to know if it is possible to avoid adding several times the same foreign key constraint? Example: if I execute 3 times the query below, the constraint will exist with 3 times in phpmyadmin… It would be great that it would be rejected the second and third time I apply that query. Answer You can g…