fix: Fix bug when delete multiply rows in one transaction

[santongding]

• Previously, Next after a Delete opcode always end due to the cursor points to an empty node
• According to https://www.sqlite.org/opcode.html#Delete, when encounter flag OPFLAG_SAVEPOSITION, should move cursor to next or previous record
• Chosen to move to the previous record, and add a hidden node at the head of the rbtree to avoid complexity

[santongding]

Hi! I'm so glad to see such a project. When I was using it, I found some bugs and tried to fix them. Also, I think there should be some test methods to verify the correctness of the transaction results, besides only checking if the transaction executed successfully.

[hananbeer]

thank you, this project was an experiment and it is not maintained. feel free to do as you please

[hananbeer]

btw this project doesn't aim to maintain 1:1 compatibility. maybe at first but I realized this isn't reasonable in solidity/evm.

there are other interesting approaches to bring sql to blockchains and blockchains to sql.

[santongding]

btw this project doesn't aim to maintain 1:1 compatibility. maybe at first but I realized this isn't reasonable in solidity/evm.

Whatever, I think this pr is just to fix a bug to ensure the project functions as intended. Beyond that, what this project attracts me is exactly its compatibility, and its a good tutorial for learning bytecode of sqlite, while performance is not a primary concern in EVM.

[ElasticBottle]

@hananbeer why do you think this isn't reasonable in solity btw?

Aside from the fact that gas might be a lot?

[hananbeer]

@hananbeer why do you think this isn't reasonable in solity btw?

Aside from the fact that gas might be a lot?

just gas.
if you want to be fully compatible with sqlite then it will cost even more gas, but I don't think this is the right approach. probably equivalency to some extent.

but good news, since then a few good opcodes have been introduced such as TLOAD/TSTORE and MCOPY as well as rollups becoming reality it is quite feasible.
open to collab on this.

[ElasticBottle]

What are the right opcodes to be looking at // where did you learn about them?

Do think it's a pretty cool idea that should be unlock by L2/L3s

I think if we can get strings unlocked and joins, this is more than shippable as alpha software