[MDEV-12326] Implement multiple-table UPDATE/DELETE returning a result set Created: 2017-03-22  Updated: 2023-10-18

Status: Open
Project: MariaDB Server
Component/s: Data Manipulation - Delete, Data Manipulation - Update
Fix Version/s: None

Type: Task Priority: Major
Reporter: Igor Babaev Assignee: Sergei Golubchik
Resolution: Unresolved Votes: 0
Labels: gsoc17, gsoc18, gsoc19, gsoc20

Issue Links:
Blocks
is blocked by MDEV-5092 Implement UPDATE with result set In Review
Duplicate
duplicates MDEV-10448 DELETE ... RETURNING support for mult... Closed
Relates
relates to MDEV-5092 Implement UPDATE with result set In Review
relates to MDEV-19093 [Feature] Issue #48 SELECT...FROM UPDATE Closed
relates to MDEV-20033 sql_mode="oracle" does not support IN... Closed

 Description   

A multiple-table UPDATE first performs join operations, then it updates the matching rows.
A multiple-table UPDATE returning a result set does the following:

  • first performs join operations
  • for each row of the result of the join it calculates some expressions over the columns of the join and forms from them a row of the returned result set
  • after this it updates the matching rows

A multiple-table DELETE first performs join operations, then it deletes the matching rows.
A multiple-table DELETE returning a result set does the following:

  • first performs join operations
  • for each row of the result of the join it calculates some expressions over the columns of the join and forms from them a row of the returned result set
  • after this it deletes the matching rows

 Comments   
Comment by Jabbar Memon [ 2017-03-26 ]

hi is this issue is assign to anyone or it is by default it is assign...

Comment by Igor Babaev [ 2017-03-28 ]

Hi Jabbar,

No, this task is open for any student.

Comment by Shubham Tomar [ 2018-03-17 ]

Hi,

My name is Shubham Tomar and I'm a final Computer Science and Engineering student at KIIT University, India.

I have previously worked at Amazon India Development Centre as an SDE(Intern) for 6 months.

I would like to work on this project as a part of GSoC '18.
Where and How can I begin?

Comment by Sergei Golubchik [ 2018-03-20 ]

You could check how MDEV-3814 was implemented. There's also a related MDEV-5092, still open.

But as far as this one is concerned, see how mutli-table UPDATE/DELETE work. Take a look at select_result class — this is what SELECT uses to send results to the client. And multi_delete and multi_update classes.

Comment by Khaled Emara [ 2020-03-19 ]

Hi,

I'm Khaled from Egypt. I'm interested in participating in GSoC this year. Any reason this project hasn't been picked up the previous years? Seems like it garnered enough attention from students. Did Google refuse the proposals?

Anyways, so to clarify: This project is about implementing the RETURNING statement for multiple tables UPDATE/DELETE? Or rather implement the the UPDATE/DELETE itself with - of course - RETURNING?

I have downloaded and built MariaDB server. Is there any qualification tasks?

Comment by Igor Babaev [ 2020-03-19 ]

Hi Khaled,
A student tried to implement this for GSoc19, but the attempt was not successful though the task was not harder than INSERT ... RETURNING (see MDEV-10014) that was implemented by another student and finally incorporated into MariaDB. You can look at the implementation of MDEV-10014 to figure out how much work it would be to implement UPDATE ... RETURNING.

Comment by Mohammed Hammaad Mateen [ 2020-03-19 ]

Greetings! I'm Hammaad, it is really interesting to know how MDEV-10014 was implemented, thank you @Igor Babaev for the information, I'd like to receive some more hints on this topic if available, as it will help me and Khaled as well.
Moreover I would love to contribute to solve this requirement.
Thanks

Comment by Igor Babaev [ 2020-03-20 ]

Hi Hammaad,
Have you built MariaDB server from the tree git@github.com:MariaDB/server.git?
If so, have you checked in debugger how INSERT ... RETURNING works?

Comment by Mohammed Hammaad Mateen [ 2020-03-20 ]

Greetings! Yes, I've built the Awesome Maria DB server. Working on MDEV-14558 currently, once done will surely look upon MDEV-10014.

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