Research delete behaviors with PostgreSQL and EF Core #1205
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
…//learn.microsoft.com/en-us/ef/core/saving/cascade-delete#database-cascade-limitations The article states various limitations in SQL Server: > Some databases, most notably SQL Server, have limitations on the cascade behaviors that form cycles. > Using cascading deletes and cascading nulls in the database at the same time will almost always result in relationship cycles when using SQL Server. When all related entities are loaded in the EF Core change tracker upfront, EF Core is able to handle the scenario by issuing multiple SQL statements. And that's why the default delete behavior for optional relationships is `ClientSetNull` instead of `SetNull`. The tests in this commit show that PostgreSQL handles the presented scenario successfully. Letting the database handle cascading is a lot more efficient.
bkoelman
force-pushed
the
delete-behaviors
branch
from
7517f30 to
c008d05
Compare
Codecov Report
@@ Coverage Diff @@
## master #1205 +/- ##
=======================================
Coverage 92.69% 92.69%
=======================================
Files 243 243
Lines 7803 7803
=======================================
Hits 7233 7233
Misses 570 570 Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here. |
|
Picture of the used model below.
|
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Added model and tests that represent the scenario described at https://learn.microsoft.com/en-us/ef/core/saving/cascade-delete#database-cascade-limitations
The article states various limitations in SQL Server:
When all related entities are loaded in the EF Core change tracker upfront, EF Core is able to handle the scenario by issuing multiple SQL statements. And that's why the default delete behavior for optional relationships is
ClientSetNullinstead ofSetNull.The tests in this commit show that PostgreSQL handles the presented scenario successfully. Letting the database handle cascading is a lot more efficient.
NOTE: This PR was created to demonstrate that the default
ClientSetNullisn't the best choice for PostgreSQL. Not intended for merging.