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[Wb-discuss] Re: WB relational database
From: |
Aubrey Jaffer |
Subject: |
[Wb-discuss] Re: WB relational database |
Date: |
Thu, 15 Apr 2010 14:44:18 -0400 (EDT) |
| Date: Wed, 14 Apr 2010 13:18:37 -0400
| From: zhang xin cheng <address@hidden>
|
| ...
| We wanna store the tuples in the b-tree. But I am wondering how I
| gonna do query them by one of the element in the tuple. e.g.
| ppl, score
| (John, 92)
| (Mike, 83)
| (Kevin, 92)
|
| how I gonna select where o = 92.
|
| Do u have some suggestions or Wbtree can build relational database
| in some way?
SLIB has a relational-database module
<http://people.csail.mit.edu/jaffer/slib_6.html> which works with
rWB-ISAM <http://people.csail.mit.edu/jaffer/wb_7.html> in SCM
<http://people.csail.mit.edu/jaffer/SCM>.
The Windows-installer for SCM includes WB. Follow the "x86 MS-Windows
Installation" instructions on
<http://people.csail.mit.edu/jaffer/FreeSnell>.
| Btw, I also wanna know the time complexity of bt-scan, it use
| b-tree structure or it just scan all the leaves of the btree?
It scans the leaves rather than repeatedly descending from the root,
making it O(N) instead of O(N log(N)).
| There is no threading in Windows since I saw that by preprocessor
| of C compiler, it didn't include pthread.h under windows
| environment right, so there is no thread implementation for
| windows?
Concurrent execution is supported in Windows.
In "wbsys.c" WB uses Windows _InterlockedExchange()
<http://msdn.microsoft.com/en-us/library/ms683590%28VS.85%29.aspx> as
its mutex when compiled by _MSC_VER (Microsoft Visual Studio).
To use pthreads under Windows, try adding "#define unix" to "wbsys.h".
You may need to add "#undef unix" to the top of "blkio.c". If that
works, I will rework the unix conditionals.