Database Administrators Stack Exchange
Database Administrators Stack Exchange

Questions tagged [cascade]

50 questions
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Why can't we have multiple cascade paths?

You can see that many questions have being asked about multiple cascade paths. For example: https://stackoverflow.com/questions/851625/foreign-key-constraint-may-cause-cycles-or-multiple-cascade-paths…
Saeed Neamati
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Postgres suggests "Truncate table ... at the same time"

When running: TRUNCATE TABLE YYYYY RESTART IDENTITY I am seeing this error message: ERROR: cannot truncate a table referenced in a foreign key constraint DETAIL: Table "XXXXX" references "YYYYY". HINT: Truncate table "XXXXX" at the same time, or…
davetapley
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10
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Cycles or multiple cascade paths with on delete set null: really?

I'm asking this question to check if my reasoning about cascaded delete is correct and if I'm not overlooking anything. I understand the behavior and I'm not asking why it is implemented with the current restrictions. When we try to create a table…
Gert Arnold
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DROP TABLE ... CASCADE does not drop any dependent table

I am still relatively new to psql and I was just finishing an assignment when I decided to try something which was to drop a table which other tables depend on due to a foreign key relationship. My expectation was that any table that had a foreign…
smac89
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Can I use `on delete set null` on a compound foreign key which contains a primary key column?

The docs say: Restricting and cascading deletes are the two most common options. RESTRICT prevents deletion of a referenced row. NO ACTION means that if any referencing rows still exist when the constraint is checked, an error is raised; this is…
Jack Douglas
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5
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Foreign key set to cascading but fails to update - why?

As mentioned elsewhere, I am rather new to SQL and databases. Getting my hands dirty at the moment and trying all the different possibilities. I have a server running MySQL and set up the following table for testing: Field Type …
koljanep
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Solving ON DELETE CASCADE cycles with triggers on MS SQL Server

I have code that is working fine in PostgreSQL and I now have to port it to MS SQL Server. It involves tables with potential cycles on delete/update events and SQL Server is complaining about it: -- TABLE t_parent CREATE TABLE t_parent (m_id INT…
Matthieu
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Alter ON DELETE CASCADE in 1 table

I'm really new to ON DELETE CASCADE. How can I delete child comments when the parent comment gets deleted in a table? Table Schema 'CREATE TABLE `comments` ( `id` int(11) NOT NULL AUTO_INCREMENT, `parent` int(11) NOT NULL, `comment`…
Farhad Nežad
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Complex Delete Cascade Including Self-Referencing Table

Above is a diagram of my data structure. It represents a hierarchy which can contain three different types of "elements": "A"s, "B"s and "C"s. The relationships show the delete cascade behavior I would like to use if it were possible. All types…
Keith Stein
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Standard Behaviour for mix of 'ON-DELETE-CASCADE' and 'ON-DELETE-RESTRICT' constraints in Mysql

In mysql 5.6, Consider these 2 examples creating relationships between A, B, C and D. Example 1 CREATE TABLE `a` ( id INT UNSIGNED NOT NULL, PRIMARY KEY (id) ) ENGINE = INNODB; CREATE TABLE `b` ( id INT UNSIGNED NOT NULL, a INT…
Dinesh Kumar
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Is there anything wrong with linking two identical primary keys in two different tables?

As you can see here, in OrderInfo and OrderNumber, I have a relationship set. But I'm not sure what kind. I was hoping to set a relationship so if I deleted an OrderNumber, it would cascade delete the corresponding record in OrderInfo, but it won't…
user18139
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TSQL: How to DELETE in cascade without altering table / indexes

I have inserted some data in a table where I should not have. I am trying to delete the data, but it has a 1:M relationship and I need to also delete data that references this one. I do not want to alter the tables / indexes, I just need this…
BogdanBiv
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Soft ON DELETE CASCADE

I am familiar with the ON DELETE CASCADE method, but I don't want to do a real delete, just a soft delete. This is implemented with a column named isDeleted (0/1). Is there a way for me to cascade this soft delete from a parent to a child? A built…
oneteen
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Can I enforce cascade delete in a delete from statement?

I am using constraints in a database meaning that records of a certain table cannot be removed lightly. That is normally the desired case. However, is there a way to write a DELETE FROM query so that for every constraint that would normally block…
Anders Lindén
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Is there a possibility to see cascade path in MS SQL

I'm having trouble with creating a foreign key in a database, because of multiple cascade paths. I am aware of some of my FKs cascading the delete, but I cannot traverse back to find the multiple cascade path. So I'm trying to find a way to…
TGlatzer
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