]>
Commit | Line | Data |
---|---|---|
fea681da MK |
1 | .\" Copyright (c) 1990, 1993 |
2 | .\" The Regents of the University of California. All rights reserved. | |
3 | .\" | |
a9cd9cb7 | 4 | .\" %%%LICENSE_START(BSD_4_CLAUSE_UCB) |
fea681da MK |
5 | .\" Redistribution and use in source and binary forms, with or without |
6 | .\" modification, are permitted provided that the following conditions | |
7 | .\" are met: | |
8 | .\" 1. Redistributions of source code must retain the above copyright | |
9 | .\" notice, this list of conditions and the following disclaimer. | |
10 | .\" 2. Redistributions in binary form must reproduce the above copyright | |
11 | .\" notice, this list of conditions and the following disclaimer in the | |
12 | .\" documentation and/or other materials provided with the distribution. | |
13 | .\" 3. All advertising materials mentioning features or use of this software | |
14 | .\" must display the following acknowledgement: | |
15 | .\" This product includes software developed by the University of | |
16 | .\" California, Berkeley and its contributors. | |
17 | .\" 4. Neither the name of the University nor the names of its contributors | |
18 | .\" may be used to endorse or promote products derived from this software | |
19 | .\" without specific prior written permission. | |
20 | .\" | |
21 | .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
22 | .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
23 | .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
24 | .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
25 | .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
26 | .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
27 | .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
28 | .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
29 | .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
30 | .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
31 | .\" SUCH DAMAGE. | |
8c9302dc | 32 | .\" %%%LICENSE_END |
fea681da MK |
33 | .\" |
34 | .\" @(#)recno.3 8.5 (Berkeley) 8/18/94 | |
35 | .\" | |
4b8c67d9 | 36 | .TH RECNO 3 2017-09-15 "" "Linux Programmer's Manual" |
fea681da MK |
37 | .UC 7 |
38 | .SH NAME | |
39 | recno \- record number database access method | |
40 | .SH SYNOPSIS | |
41 | .nf | |
42 | .ft B | |
43 | #include <sys/types.h> | |
44 | #include <db.h> | |
45 | .ft R | |
46 | .fi | |
47 | .SH DESCRIPTION | |
df21098d MK |
48 | .IR "Note well" : |
49 | This page documents interfaces provided in glibc up until version 2.1. | |
50 | Since version 2.2, glibc no longer provides these interfaces. | |
51 | Probably, you are looking for the APIs provided by the | |
52 | .I libdb | |
53 | library instead. | |
847e0d88 | 54 | .PP |
fea681da | 55 | The routine |
1c9d4f95 | 56 | .BR dbopen (3) |
fea681da MK |
57 | is the library interface to database files. |
58 | One of the supported file formats is record number files. | |
59 | The general description of the database access methods is in | |
31e9a9ec | 60 | .BR dbopen (3), |
76c637e1 | 61 | this manual page describes only the recno-specific information. |
fea681da MK |
62 | .PP |
63 | The record number data structure is either variable or fixed-length | |
64 | records stored in a flat-file format, accessed by the logical record | |
65 | number. | |
66 | The existence of record number five implies the existence of records | |
67 | one through four, and the deletion of record number one causes | |
68 | record number five to be renumbered to record number four, as well | |
69 | as the cursor, if positioned after record number one, to shift down | |
70 | one record. | |
71 | .PP | |
76c637e1 | 72 | The recno access-method-specific data structure provided to |
1c9d4f95 | 73 | .BR dbopen (3) |
a9a13a50 MK |
74 | is defined in the |
75 | .I <db.h> | |
76 | include file as follows: | |
fea681da | 77 | .PP |
088a639b | 78 | .in +4n |
b8302363 | 79 | .EX |
fea681da | 80 | typedef struct { |
c09cb5f4 | 81 | unsigned long flags; |
aeb4b1fc MK |
82 | unsigned int cachesize; |
83 | unsigned int psize; | |
84 | int lorder; | |
85 | size_t reclen; | |
10ff70c5 | 86 | unsigned char bval; |
aeb4b1fc | 87 | char *bfname; |
fea681da | 88 | } RECNOINFO; |
b8302363 | 89 | .EE |
ec5a588f | 90 | .in |
fea681da MK |
91 | .PP |
92 | The elements of this structure are defined as follows: | |
93 | .TP | |
fac55da5 | 94 | .I flags |
cebca1bd | 95 | The flag value is specified by ORing |
fea681da MK |
96 | any of the following values: |
97 | .RS | |
98 | .TP | |
4bd8c614 | 99 | .B R_FIXEDLEN |
fea681da MK |
100 | The records are fixed-length, not byte delimited. |
101 | The structure element | |
102 | .I reclen | |
103 | specifies the length of the record, and the structure element | |
104 | .I bval | |
105 | is used as the pad character. | |
106 | Any records, inserted into the database, that are less than | |
107 | .I reclen | |
108 | bytes long are automatically padded. | |
109 | .TP | |
4bd8c614 | 110 | .B R_NOKEY |
fea681da | 111 | In the interface specified by |
1c9d4f95 | 112 | .BR dbopen (3), |
fea681da MK |
113 | the sequential record retrieval fills in both the caller's key and |
114 | data structures. | |
4bd8c614 MK |
115 | If the |
116 | .B R_NOKEY | |
117 | flag is specified, the | |
fea681da MK |
118 | .I cursor |
119 | routines are not required to fill in the key structure. | |
120 | This permits applications to retrieve records at the end of files without | |
121 | reading all of the intervening records. | |
122 | .TP | |
4bd8c614 | 123 | .B R_SNAPSHOT |
fea681da | 124 | This flag requires that a snapshot of the file be taken when |
1c9d4f95 | 125 | .BR dbopen (3) |
fea681da MK |
126 | is called, instead of permitting any unmodified records to be read from |
127 | the original file. | |
128 | .RE | |
129 | .TP | |
ec5a588f | 130 | .I cachesize |
fea681da MK |
131 | A suggested maximum size, in bytes, of the memory cache. |
132 | This value is | |
133 | .B only | |
134 | advisory, and the access method will allocate more memory rather than fail. | |
135 | If | |
136 | .I cachesize | |
f89652a6 | 137 | is 0 (no size is specified), a default cache is used. |
fea681da | 138 | .TP |
ec5a588f | 139 | .I psize |
fea681da MK |
140 | The recno access method stores the in-memory copies of its records |
141 | in a btree. | |
142 | This value is the size (in bytes) of the pages used for nodes in that tree. | |
143 | If | |
144 | .I psize | |
f89652a6 | 145 | is 0 (no page size is specified), a page size is chosen based on the |
9ee4a2b6 | 146 | underlying filesystem I/O block size. |
fea681da | 147 | See |
31e9a9ec | 148 | .BR btree (3) |
fea681da MK |
149 | for more information. |
150 | .TP | |
ec5a588f | 151 | .I lorder |
fea681da MK |
152 | The byte order for integers in the stored database metadata. |
153 | The number should represent the order as an integer; for example, | |
154 | big endian order would be the number 4,321. | |
155 | If | |
156 | .I lorder | |
f89652a6 | 157 | is 0 (no order is specified), the current host order is used. |
fea681da | 158 | .TP |
ec5a588f | 159 | .I reclen |
fea681da MK |
160 | The length of a fixed-length record. |
161 | .TP | |
ec5a588f | 162 | .I bval |
fea681da MK |
163 | The delimiting byte to be used to mark the end of a record for |
164 | variable-length records, and the pad character for fixed-length | |
165 | records. | |
31a6818e | 166 | If no value is specified, newlines ("\en") are used to mark the end |
fea681da MK |
167 | of variable-length records and fixed-length records are padded with |
168 | spaces. | |
169 | .TP | |
ec5a588f | 170 | .I bfname |
fea681da MK |
171 | The recno access method stores the in-memory copies of its records |
172 | in a btree. | |
ec5a588f MK |
173 | If |
174 | .I bfname | |
175 | is non-NULL, it specifies the name of the btree file, | |
1c9d4f95 MK |
176 | as if specified as the filename for a |
177 | .BR dbopen (3) | |
178 | of a btree file. | |
fea681da | 179 | .PP |
ec5a588f MK |
180 | The data part of the key/data pair used by the |
181 | .I recno | |
182 | access method | |
fea681da MK |
183 | is the same as other access methods. |
184 | The key is different. | |
185 | The | |
186 | .I data | |
187 | field of the key should be a pointer to a memory location of type | |
188 | .IR recno_t , | |
cd4e22e8 | 189 | as defined in the |
ec5a588f | 190 | .I <db.h> |
a9a13a50 | 191 | include file. |
fea681da MK |
192 | This type is normally the largest unsigned integral type available to |
193 | the implementation. | |
194 | The | |
195 | .I size | |
196 | field of the key should be the size of that type. | |
197 | .PP | |
466dbc8b | 198 | Because there can be no metadata associated with the underlying |
fea681da | 199 | recno access method files, any changes made to the default values |
75b94dc3 | 200 | (e.g., fixed record length or byte separator value) must be explicitly |
fea681da MK |
201 | specified each time the file is opened. |
202 | .PP | |
203 | In the interface specified by | |
1c9d4f95 | 204 | .BR dbopen (3), |
fea681da MK |
205 | using the |
206 | .I put | |
207 | interface to create a new record will cause the creation of multiple, | |
208 | empty records if the record number is more than one greater than the | |
209 | largest record currently in the database. | |
210 | .SH ERRORS | |
211 | The | |
212 | .I recno | |
213 | access method routines may fail and set | |
214 | .I errno | |
215 | for any of the errors specified for the library routine | |
31e9a9ec | 216 | .BR dbopen (3) |
fea681da MK |
217 | or the following: |
218 | .TP | |
747944fe | 219 | .B EINVAL |
fea681da MK |
220 | An attempt was made to add a record to a fixed-length database that |
221 | was too large to fit. | |
e37e3282 MK |
222 | .SH BUGS |
223 | Only big and little endian byte order is supported. | |
47297adb | 224 | .SH SEE ALSO |
ac5e6a36 | 225 | .BR btree (3), |
31e9a9ec MK |
226 | .BR dbopen (3), |
227 | .BR hash (3), | |
d8aaa1d3 | 228 | .BR mpool (3) |
847e0d88 | 229 | .PP |
fea681da MK |
230 | .IR "Document Processing in a Relational Database System" , |
231 | Michael Stonebraker, Heidi Stettner, Joseph Kalash, Antonin Guttman, | |
232 | Nadene Lynn, Memorandum No. UCB/ERL M82/32, May 1982. |