foreign-keys Archives - Page 3 of 3

Postgres and Indexes on Foreign Keys and Primary Keys

Does Postgres automatically put indexes on Foreign Keys and Primary Keys? How can I tell? Is there a command that will return all ...

May 7, 2022
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How to select rows with no matching entry in another table?

I’m doing some maintenance work on a database application and I’ve discovered that, joy of joys, even though values from one table are ...

May 7, 2022
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When to use “ON UPDATE CASCADE”

I use ON DELETE CASCADE regularly but I never use ON UPDATE CASCADE as I am not so sure in what situation it ...

May 4, 2022
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MySQL DROP all tables, ignoring foreign keys

Is there a nice easy way to drop all tables from a MySQL database, ignoring any foreign key constraints that may be in ...

May 2, 2022
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Cannot truncate table because it is being referenced by a FOREIGN KEY constraint?

Using MSSQL2005, can I truncate a table with a foreign key constraint if I first truncate the child table (the table with the ...

May 2, 2022
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What is related_name used for?

What is the related_name argument useful for on ManyToManyField and ForeignKey fields? For example, given the following code, what is the effect of ...

May 1, 2022
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How do I see all foreign keys to a table or column?

In MySQL, how do I get a list of all foreign key constraints pointing to a particular table? a particular column? This is ...

April 28, 2022
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How to truncate a foreign key constrained table?

Why doesn’t a TRUNCATE on mygroup work? Even though I have ON DELETE CASCADE SET I get: ERROR 1701 (42000): Cannot truncate a ...

April 22, 2022
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How can foreign key constraints be temporarily disabled using T-SQL?

Are disabling and enabling foreign key constraints supported in SQL Server? Or is my only option to drop and then re-create the constraints? ...

April 18, 2022
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