diff options
Diffstat (limited to 'lib/libc/db/man/recno.3')
| -rw-r--r-- | lib/libc/db/man/recno.3 | 228 |
1 files changed, 228 insertions, 0 deletions
diff --git a/lib/libc/db/man/recno.3 b/lib/libc/db/man/recno.3 new file mode 100644 index 0000000..22d5567 --- /dev/null +++ b/lib/libc/db/man/recno.3 @@ -0,0 +1,228 @@ +.\" 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. +.\" 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. +.\" +.\" @(#)recno.3 8.5 (Berkeley) 8/18/94 +.\" $FreeBSD$ +.\" +.Dd August 18, 1994 +.Dt RECNO 3 +.Os +.Sh NAME +.Nm recno +.Nd "record number database access method" +.Sh SYNOPSIS +.In sys/types.h +.In db.h +.Sh DESCRIPTION +The routine +.Fn dbopen +is the library interface to database files. +One of the supported file formats is record number files. +The general description of the database access methods is in +.Xr dbopen 3 , +this manual page describes only the +.Nm +specific information. +.Pp +The record number data structure is either variable or fixed-length +records stored in a flat-file format, accessed by the logical record +number. +The existence of record number five implies the existence of records +one through four, and the deletion of record number one causes +record number five to be renumbered to record number four, as well +as the cursor, if positioned after record number one, to shift down +one record. +.Pp +The +.Nm +access method specific data structure provided to +.Fn dbopen +is defined in the +.In db.h +include file as follows: +.Bd -literal +typedef struct { + u_long flags; + u_int cachesize; + u_int psize; + int lorder; + size_t reclen; + u_char bval; + char *bfname; +} RECNOINFO; +.Ed +.Pp +The elements of this structure are defined as follows: +.Bl -tag -width indent +.It Va flags +The flag value is specified by +.Em or Ns 'ing +any of the following values: +.Bl -tag -width indent +.It Dv R_FIXEDLEN +The records are fixed-length, not byte delimited. +The structure element +.Va reclen +specifies the length of the record, and the structure element +.Va bval +is used as the pad character. +Any records, inserted into the database, that are less than +.Va reclen +bytes long are automatically padded. +.It Dv R_NOKEY +In the interface specified by +.Fn dbopen , +the sequential record retrieval fills in both the caller's key and +data structures. +If the +.Dv R_NOKEY +flag is specified, the +.Em cursor +routines are not required to fill in the key structure. +This permits applications to retrieve records at the end of files without +reading all of the intervening records. +.It Dv R_SNAPSHOT +This flag requires that a snapshot of the file be taken when +.Fn dbopen +is called, instead of permitting any unmodified records to be read from +the original file. +.El +.It Va cachesize +A suggested maximum size, in bytes, of the memory cache. +This value is +.Em only +advisory, and the access method will allocate more memory rather than fail. +If +.Va cachesize +is 0 (no size is specified) a default cache is used. +.It Va psize +The +.Nm +access method stores the in-memory copies of its records +in a btree. +This value is the size (in bytes) of the pages used for nodes in that tree. +If +.Va psize +is 0 (no page size is specified) a page size is chosen based on the +underlying file system I/O block size. +See +.Xr btree 3 +for more information. +.It Va lorder +The byte order for integers in the stored database metadata. +The number should represent the order as an integer; for example, +big endian order would be the number 4,321. +If +.Va lorder +is 0 (no order is specified) the current host order is used. +.It Va reclen +The length of a fixed-length record. +.It Va bval +The delimiting byte to be used to mark the end of a record for +variable-length records, and the pad character for fixed-length +records. +If no value is specified, newlines +.Pq Dq \en +are used to mark the end +of variable-length records and fixed-length records are padded with +spaces. +.It Va bfname +The +.Nm +access method stores the in-memory copies of its records +in a btree. +If +.Va bfname +is +.No non\- Ns Dv NULL , +it specifies the name of the btree file, +as if specified as the file name for a +.Fn dbopen +of a btree file. +.El +.Pp +The data part of the key/data pair used by the +.Nm +access method +is the same as other access methods. +The key is different. +The +.Va data +field of the key should be a pointer to a memory location of type +.Ft recno_t , +as defined in the +.In db.h +include file. +This type is normally the largest unsigned integral type available to +the implementation. +The +.Va size +field of the key should be the size of that type. +.Pp +Because there can be no meta-data associated with the underlying +.Nm +access method files, any changes made to the default values +(e.g.\& fixed record length or byte separator value) must be explicitly +specified each time the file is opened. +.Pp +In the interface specified by +.Fn dbopen , +using the +.Va put +interface to create a new record will cause the creation of multiple, +empty records if the record number is more than one greater than the +largest record currently in the database. +.Sh ERRORS +The +.Nm +access method routines may fail and set +.Va errno +for any of the errors specified for the library routine +.Xr dbopen 3 +or the following: +.Bl -tag -width Er +.It Bq Er EINVAL +An attempt was made to add a record to a fixed-length database that +was too large to fit. +.El +.Sh SEE ALSO +.Xr btree 3 , +.Xr dbopen 3 , +.Xr hash 3 , +.Xr mpool 3 +.Rs +.%T "Document Processing in a Relational Database System" +.%A Michael Stonebraker +.%A Heidi Stettner +.%A Joseph Kalash +.%A Antonin Guttman +.%A Nadene Lynn +.%R "Memorandum No. UCB/ERL M82/32" +.%D May 1982 +.Re +.Sh BUGS +Only big and little endian byte order is supported. |
