[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[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

The Windows-installer for SCM includes WB.  Follow the "x86 MS-Windows
Installation" instructions on

 | 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.

reply via email to

[Prev in Thread] Current Thread [Next in Thread]