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By Alfredo Sanchez (alfy) on Feb 12, 2011 6:03 AM.
SQL library
Ciao Toby,

I was wondering if you have any plans to release a new version of the SQL library: the current version is not complete (I cannot create, alter, delete nor update) and it would be great to have these features working.
The new version is cool: I like the OODB library, but SQL is more standard...

By Tobias Downer (toby) on Feb 12, 2011 12:36 PM.
I would love to have a more complete SQL library! I too think this is an important feature. Unfortunately my priority at the moment is for administration and auditing tools, and improvements in the general accessibility of MckoiDDB to developers.

There will be a code repository up for this module soon and I will be taking contributions for it.
By Alfredo Sanchez (alfy) on Feb 13, 2011 7:48 AM.
It's a great news about the efforts you're putting on admin tools: I agree they are really a key components in such kind of applications.

Personally, I can say I'm just a lurker: watching at your SQL code, I don't feel I can really make a contribution, since its complexity (especially the whole OperationPlanner and similar classes). The only thing I could do is supporting you morally (and eventually donating few buck) ... ;)

By the way, I will keep watching evolutions on your code and eventually see if I could make a contribution somewhere ...

By Alfredo Sanchez (alfy) on Mar 11, 2011 4:45 AM.

Sorry to bother you about this, but I took some time to review the code of McKoiDDBSQL Beta (that is based on McKoiDDB 1.0) and the code of McKoiDDB 1.2, that includes the new consensus function ObjectDatabase, and I noticed the new approach based on binary serialization (also of the strings) you took for the second one: is it possible you will refactor the SQL library to support this binary serialization too?

Also, there's a big lack in the SQL library, that is the constraints implementation: can you explain why haven't you implemented it? Is it planned? Is that complex to enforce constraint checking at commit?


PS. you commented that you're setting up a code repository for contributions: is it possible to have a hunch on where is it located?
By Tobias Downer (toby) on Mar 11, 2011 2:31 PM.
You should be able to use the SQL data model with MckoiDDB 1.2 with no changes. You just need to recompile the source against the new version. I'm not sure at this time if I will revisit the data format for the SQL model but I imagine there could be some incremental changes made that will include some of the new 1.2 data structures. The binary transaction log that was implemented in the new ObjectDatabase is perhaps the one feature I think this data model does better than in the SQL model.

Referential integrity constraints would not be complicated to add. It is a matter of time that they are not currently included.

I'm currently hard working on preparing a series of major changes to the website which will include the code repository. More news about this soon.
By Alfredo Sanchez (alfy) on Mar 11, 2011 4:55 PM.
Great news! Integrity constraints are basically the only missing part in the SQL library (I think): it is in fact easy to implement the DML and DDL statements (maybe already done: I've played just with the SELECT statement, like in the demo).

By the way, I'd like to help you with this as much as I can (actually very a little), debugging and implementing: I really appreciate your work and this looks an interesting project to work on to learn the SQL model more (at least "in the hood": I passed the exam on databases and SQL last month).
I guess this you have planned to implement also the features of INFORMATION_SCHEMA and the JDBC client? Maybe I could help? Triggers? Can you make me a list of feature you're planning and tell me where/if I can collaborate?

I can't wait to see your public repository: I hope it will be a Git, so that I can collaborate offline.

By Tobias Downer (toby) on Mar 11, 2011 6:02 PM.
What you see is as far as I've reached with the SQL model. New features that are the simplest to implement in its current state would be the ones you've mentioned actually - JDBC, fleshing out the SQL grammar, referential integrity constraints. Except SQL triggers - this is a rather challenging feature for a distributed system and would require some infrastructure additions to MckoiDDB (ie. some sort of distributed fault-tolerant event mechanism).
By Alfredo Sanchez (alfy) on Mar 13, 2011 2:20 PM.
it's really fascinating to see how a database system is developed. actually, my main concerns are about our (and other's) concurrent work: it's true that as a student I have a some free time to dedicate to it, but I can't really think of starting contributing, at the moment, cause I could make a lot of work and no way to coordinate us, so that at the end the two branches of the code would be so different to be incompatible.
this is the reason why I was asking you about a VCS: also, where could I post my contributions otherwise? ;)

I'm thrilled to see the latest version of the SQL library: there are so many missing pieces (practically, everything except SELECT, that works well by the way), and I've been thinking a lot about what I could have implement myself, but I've been frustrated by the reason above ...

By Alfredo Sanchez (alfy) on Mar 14, 2011 5:14 AM.
Making a brief research on Google about the past project (McKoi database), I noticed this link

I've downloaded the package and watched the entire source attentively: I noticed that basically, the entire infrastructure of the McKoiDDB SQL library is based on the McKoi 2.0 project. I like it! ;)
Are you working to integrate the code of the old project into the MckoiDDB SQL library, or should I expect you to redo the whole stuff? *Personally*, I'd go for the solution of using what exists already, without "reinventing the wheel" (like my prof. says when we try to answer more than requested) ...

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