Implement FK constraints as depicted in ER-diagram
Nov 9, 2023 · Then FK columns can mostly share the same name, making everything clearer and queries on multiple connected tables simpler. What's more, there is a many-to-many relationship …
INSERT statement conflicted with the FOREIGN KEY constraint - SQL ...
The way a FK works is it cannot have a value in that column that is not also in the primary key column of the referenced table. What is missing from that answer is: You must build the table containing the …
Does a foreign key automatically create an index?
An FK-relationship will often need to look up a relating table and extract certain rows based on a single value or a range of values. So it makes good sense to index any columns involved in an FK, but an …
sql - How to place FK constraint so that deleting a single FK record ...
Feb 6, 2025 · I did create a FK constraint in the child table with ON DELETE CASCADE thinking that this would delete only the child-table record when a child table delete record operation is intended …
How do I drop a foreign key in SQL Server? - Stack Overflow
Sep 18, 2008 · Your syntax for dropping the FK doesn't need the words "foreign key". This is the syntax for MySQL, not SQL Server. You can replace it with the word "constraint".
How do I create a foreign key in SQL Server? - Stack Overflow
I agree naming constraints is a good plan but, in SQL Server 2008 R2 at least, the syntax of the last line has to be "constraint fk_questionbank_exams foreign key (question_exam_id) references exams …
How do I use cascade delete with SQL Server? - Stack Overflow
To add "Cascade delete" to an existing foreign key in SQL Server Management Studio: First, select your Foreign Key, and open its "DROP And CREATE To.." in a new Query window. Then, just add ON …
List of foreign keys and the tables they reference in Oracle DB
Mar 19, 2019 · I'm trying to find a query which will return me a list of the foreign keys for a table and the tables and columns they reference. I am half way there with SELECT a.table_name, a.column_n...
How to create a foreign key in phpmyadmin - Stack Overflow
Jun 3, 2016 · Thank you Alok! great answer I am new to using php so this is a great help - If I opt to create the foreign key using an sql statement - ` ALTER TABLE Patient ADD CONSTRAINT …
Differences between "foreign key" and "constraint foreign key"
Sep 29, 2012 · I mean for example I can create table like create table XTable ( idt int not null primary key, value nvarchar(50), idq int, constraint fk_idq foreign key(idq) references YTable(idq) ) and...