.\" Copyright (c) 1990, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"	@(#)btree.3	8.4 (Berkeley) 8/18/94
.\"
.\" Japanese Version Copyright (c) 1999 Shouichi Saito
.\"	all rights reserved.
.\" Translated Mon Jul 26 21:43:11 JST 1999
.\"	by Shouichi Saito <ss236rx@ymg.urban.ne.jp>
.\" Proofed Mon Aug 16 1999 by NAKANO Takeo <nakano@apm.seikei.ac.jp>
.\"
.\"WORD:	access method		᥽å
.\"WORD:	prefix (comparison)	
.TH BTREE 3 1994-08-18 "" "Linux Programmer's Manual"
.UC 7
.SH ̾
btree \- btree ǡ١ؤΥ᥽å
.SH 
.nf
.ft B
#include <sys/types.h>
#include <db.h>
.ft R
.fi
.SH 
롼
.BR dbopen (3)
ϥǡ١եФ饤֥ꥤ󥿡եǤ롣
ݡȤƤեեޥåȤΤҤȤĤ btree ե뤬롣
ǡ١ؤΥ᥽åɤ˴ؤŪʵҤ
.BR dbopen (3)
˽񤫤Ƥ롣
Υޥ˥奢ڡǤ btree ͭξˤĤƤΤߵҤ롣
.PP
btree ǡ¤ǤϡȤ줿Х󥹥ĥ꡼¤
ߤ˴ϢŤ줿/ǡФǼƤ롣
.PP
.BR dbopen (3)
Ϥ btree ᥽åɤͭΥǡ¤Τϡ
.I <db.h>
󥯥롼ɥեǼΤ褦Ƥ롣
.sp
.in +4n
.nf

typedef struct {
    unsigned long flags;
    unsigned int  cachesize;
    int           maxkeypage;
    int           minkeypage;
    unsigned int  psize;
    int         (*compare)(const DBT *key1, const DBT *key2);
    size_t      (*prefix)(const DBT *key1, const DBT *key2);
    int           lorder;
} BTREEINFO;
.fi
.in
.sp
ι¤ΤǤʲ˼
.TP
.I flags
.I flags
ͤϰʲͤΤ줫¤ǻꤵ롣
.RS
.TP
.B R_DUP
ĥ꡼˥νʣʤĥ꡼褦ȤƤ
¸ߤƤƤ⡢Ĥ롣ǥեȤư
.BR dbopen (3)
˵ҤƤ褦ˡȰפ񤭤롣
뤤
.B R_NOOVERWRITE
ե饰ꤵƤ˼Ԥ롣
.B R_DUP
ե饰
.B R_NOOVERWRITE
ե饰ˤäƾ񤭤롣Ĥޤ
.B R_NOOVERWRITE
ե饰ꤵ줿硢ĥ꡼ʣ褦ȤȼԤ롣
.IP
ǡ١˥νʣȡ
.I get
롼ȤäΥ/ǡФμ̤Ǥ롣Ф
.B R_CURSOR
ե饰򥻥åȤ
.I seq
롼ȤȡʣΥ롼פ
ŪˡֺǽפΥɬ֤Ƥ롣
.RE
.TP
.I cachesize
ꤵꥭåκ祵 (Хñ)
ͤ
.I ޤ
ͤǤꡢ᥽åɤϤͤۤ
Ƥ뤳Ȥ⤢롣
äơʪŪʽ񤭹ߤϲǽʸ¤ٱ䤵Τǡ
å礭Ŭ٤ˤƤ I/O β򤫤ʤ긺餹
Ǥ롣
餫˥åȤȡĥ꡼ѹƤ
ƥबå夷Υǡ˲ǡȤβǽ
 (ޤǤ⤽Τ)
.I cachesize
 0 (ꤵƤʤ) ξ硢ǥեȤΥå夬Ȥ롣
.TP
.I maxkeypage
ñڡǼ祭Ǥ롣߼Ƥʤ
.\" The maximum number of keys which will be stored on any single page.
.\" Because of the way the btree data structure works,
.\" .I maxkeypage
.\" must always be greater than or equal to 2.
.\" If
.\" .I maxkeypage
.\" is 0 (no maximum number of keys is specified) the page fill factor is
.\" made as large as possible (which is almost invariably what is wanted).
.TP
.I minkeypage
ñڡǼǾǤ롣ͤϡɤΥ
Сեڡ
Ǽ뤫Τ˻Ȥ롣ʤޤϥǡ
minkeypage ͤʬ䤵줿ڡ礭ΥڡǼ
˥СեڡǼȤȤǤ롣
.I minkeypage
 0 (κǾͤꤵƤʤ) ξ硢ͤȤ 2 Ȥ롣
.TP
.I psize
ĥ꡼ΥΡɤ˻Ȥڡ (Хñ)
Ǿͤ 512 ХȤǡͤ 64K Ǥ롣
.I psize
 0 (ڡꤵƤʤ) ξ硢
ե륷ƥ I/O ֥å˴ŤƷ롣
.TP
.I compare
.I compare
ϥӴؿǤ롣
ǽΥФܤΥ礭ˤ
Ʊˤϥ򡢾ˤ֤
ĥ꡼򳫤ݤˤϡƱӴؿȤʤФʤʤ
.I compare
 NULL (ӴؿꤵƤʤ) ξ硢
ŪӤ롣ûĹ꾮Ȥˤʤ롣
.TP
.I prefix
.I prefix
ӴؿǤ롣
Υ롼 (ꤵ줿ˤ)ܤΥ
Хȿ֤ʤƤϤʤʤܤΥ
ܤΥ礭ɤΤɬפǤ롣
.\"NAKANO äỌ̇̄狼...
Ʊ硢Ĺ֤롣Υ롼ͭѤɤϡ
ǡ˶¸롣ǡåȤˤäƤϡ餫˥ĥ꡼
Υȸ֤򸺤餷Ƥ롣
.I prefix
 NULL (prefix ؿꤵƤʤ) ǡ
.I 
ӴؿꤵƤʤȡǥեȤμӥ롼󤬻Ȥ롣
.I prefix
 NULL ӴؿꤵƤϡӤϹԤʤ
.TP
.I lorder
ǡ١˳ǼƤ᥿ǡͤΥХȥ
οϡɽΤǤ롣
㤨Хӥåǥʤ顢οͤ 4,321 Ȥʤ롣
.I lorder
 0 (ꤵƤʤ) ξ硢ߤΥۥ
ǻȤƤХȥȤ롣
.PP
ե뤬¸ߤƤ (ޤ
.B O_TRUCT
ե饰ꤵƤʤ) ȡ

.IR flag ,
.IR lorder ,
.I psize
˻ꤵ줿̵ͤ뤵졢
ĥ꡼줿˻ȤäͤѤ롣
.PP
ĥ꡼縡ϡǾ祭˸äƹԤ롣
.PP
ĥ꡼饭/ǡФ뤳ȤˤäƤǤڡϡ
̾ѤǤˤʤäƤ뤬Ѥ뤳Ȥ̵
Ĥޤ brtee ¤礹Ǥ롣
кϲ٤κ򤱤뤫
¸ߤĥ꡼Ĵ٤Ū˿ĥ꡼뤫Ǥ롣
.PP
.SH 顼
.I btree
᥽åɥ롼ϼԤȡ饤֥롼
.BR dbopen (3)
Ƥ륨顼Τ줫
.I errno
Ȥ֤
.SH Х
ХȥȤƤϥӥåǥȥȥ륨ǥΤߤ
ݡȤƤ롣
.SH Ϣ
.BR dbopen (3),
.BR hash (3),
.BR mpool (3),
.BR recno (3)
.sp
.IR "The Ubiquitous B-tree" ,
Douglas Comer, ACM Comput. Surv. 11, 2 (June 1979), 121-138.
.sp
.IR "Prefix B-trees" ,
Bayer and Unterauer, ACM Transactions on Database Systems, Vol. 2, 1
(March 1977), 11-26.
.sp
.IR "The Art of Computer Programming Vol. 3: Sorting and Searching" ,
D.E. Knuth, 1968, pp 471-480.