1 |
root |
1.1 |
=head1 NAME |
2 |
|
|
|
3 |
|
|
PApp::SQL - absolutely easy yet fast and powerful sql access |
4 |
|
|
|
5 |
|
|
=head1 SYNOPSIS |
6 |
|
|
|
7 |
|
|
use PApp::SQL; |
8 |
root |
1.10 |
|
9 |
|
|
my $st = sql_exec $DBH, "select ... where a = ?", $a; |
10 |
|
|
|
11 |
|
|
local $DBH = <database handle>; |
12 |
|
|
my $st = sql_exec \my($bind_a, $bind_b), "select a,b ..."; |
13 |
|
|
my $st = sql_insertid |
14 |
|
|
sql_exec "insert into ... values (?, ?)", $v1, $v2; |
15 |
|
|
my $a = sql_fetch "select a from ..."; |
16 |
|
|
sql_fetch \my($a, $b), "select a,b ..."; |
17 |
|
|
|
18 |
|
|
sql_exists "name from table where name like 'a%'" |
19 |
|
|
or die "a* required but not existent"; |
20 |
|
|
|
21 |
|
|
my $db = new PApp::SQL::Database "", "DBI:mysql:test", "user", "pass"; |
22 |
|
|
local $PApp::SQL::DBH = $db->checked_dbh; # does 'ping' |
23 |
|
|
|
24 |
|
|
sql_exec $db->dbh, "select ..."; |
25 |
root |
1.1 |
|
26 |
|
|
=head1 DESCRIPTION |
27 |
|
|
|
28 |
|
|
This module provides you with easy-to-use functions to execute sql |
29 |
|
|
commands (using DBI). Despite being easy to use, they are also quite |
30 |
root |
1.10 |
efficient and allow you to write faster programs in less lines of code. It |
31 |
|
|
should work with anything from perl-5.004_01 onwards, but I only support |
32 |
|
|
5.005+. |
33 |
|
|
|
34 |
|
|
If the descriptions here seem terse or if you always wanted to know |
35 |
|
|
what PApp is then have a look at the PApp module which uses this module |
36 |
|
|
extensively but also provides you with a lot more gimmicks to play around |
37 |
|
|
with to help you create cool applications ;) |
38 |
root |
1.1 |
|
39 |
|
|
=cut |
40 |
|
|
|
41 |
|
|
package PApp::SQL; |
42 |
|
|
|
43 |
root |
1.10 |
use DBI (); |
44 |
root |
1.1 |
|
45 |
|
|
BEGIN { |
46 |
root |
1.10 |
use base qw(Exporter DynaLoader); |
47 |
root |
1.1 |
|
48 |
root |
1.12 |
$VERSION = 0.121; |
49 |
root |
1.1 |
@EXPORT = qw( |
50 |
|
|
sql_exec sql_fetch sql_fetchall sql_exists sql_insertid $sql_exec |
51 |
|
|
); |
52 |
|
|
@EXPORT_OK = qw( |
53 |
|
|
connect_cached |
54 |
|
|
); |
55 |
|
|
|
56 |
root |
1.10 |
bootstrap PApp::SQL $VERSION; |
57 |
root |
1.1 |
} |
58 |
|
|
|
59 |
|
|
our $sql_exec; # last result of sql_exec's execute call |
60 |
|
|
our $DBH; # the default database handle |
61 |
root |
1.10 |
our $Database; # the current SQL::Database object, if applicable |
62 |
root |
1.1 |
|
63 |
|
|
our %dbcache; |
64 |
|
|
|
65 |
root |
1.10 |
=head2 GLOBAL VARIABLES |
66 |
|
|
|
67 |
|
|
=over 4 |
68 |
|
|
|
69 |
|
|
=item $sql_exec |
70 |
|
|
|
71 |
|
|
Since the C<sql_exec> family of functions return a statement handle there |
72 |
|
|
must eb another way to test the return value of the C<execute> call. This |
73 |
|
|
global variable contains the result of the most recent call to C<execute> |
74 |
|
|
done by this module. |
75 |
|
|
|
76 |
|
|
=item $PApp::SQL::DBH |
77 |
|
|
|
78 |
|
|
The default database handle used by this module if no C<$DBH> was |
79 |
|
|
specified as argument and no C<$DBH> is found in the current package. See |
80 |
|
|
C<sql_exec> for a discussion. |
81 |
|
|
|
82 |
|
|
=item $PApp::SQL::Database |
83 |
|
|
|
84 |
|
|
The current default C<PApp::SQL::Database>-object. Future versions might |
85 |
|
|
automatically fall back on this database and create database handles from |
86 |
|
|
it if neccessary. At the moment this is not used by this module but might |
87 |
|
|
be nice as a placeholder for the database object that corresponds to |
88 |
|
|
$PApp::SQL::DBH. |
89 |
|
|
|
90 |
|
|
=back |
91 |
|
|
|
92 |
|
|
=head2 FUNCTIONS |
93 |
|
|
|
94 |
|
|
=over 4 |
95 |
|
|
|
96 |
root |
1.1 |
=item $dbh = connect_cached $id, $dsn, $user, $pass, $flags, $connect |
97 |
|
|
|
98 |
|
|
(not exported by by default) |
99 |
|
|
|
100 |
|
|
Connect to the database given by C<($dsn,$user,$pass)>, while using the |
101 |
|
|
flags from C<$flags>. These are just the same arguments as given to |
102 |
|
|
C<DBI->connect>. |
103 |
|
|
|
104 |
root |
1.6 |
The database handle will be cached under the unique id |
105 |
|
|
C<$id|$dsn|$user|$pass>. If the same id is requested later, the |
106 |
|
|
cached handle will be checked (using ping), and the connection will |
107 |
|
|
be re-established if necessary (be sure to prefix your application or |
108 |
|
|
module name to the id to make it "more" unique. Things like __PACKAGE__ . |
109 |
|
|
__LINE__ work fine as well). |
110 |
|
|
|
111 |
|
|
The reason C<$id> is necessary is that you might specify special connect |
112 |
|
|
arguments or special flags, or you might want to configure your $DBH |
113 |
|
|
differently than maybe other applications requesting the same database |
114 |
|
|
connection. If none of this is becessary for your application you can |
115 |
|
|
leave $id empty (i.e. ""). |
116 |
root |
1.1 |
|
117 |
|
|
If specified, C<$connect> is a callback (e.g. a coderef) that will be |
118 |
|
|
called each time a new connection is being established, with the new |
119 |
|
|
C<$dbh> as first argument. |
120 |
|
|
|
121 |
|
|
Examples: |
122 |
|
|
|
123 |
|
|
# try your luck opening the papp database without access info |
124 |
|
|
$dbh = connect_cached __FILE__, "DBI:mysql:papp"; |
125 |
|
|
|
126 |
|
|
=cut |
127 |
|
|
|
128 |
|
|
sub connect_cached { |
129 |
|
|
my ($id, $dsn, $user, $pass, $flags, $connect) = @_; |
130 |
|
|
# the following line is duplicated in PApp::SQL::Database::new |
131 |
|
|
$id = "$id\0$dsn\0$user\0$pass"; |
132 |
|
|
unless ($dbcache{$id} && $dbcache{$id}->ping) { |
133 |
|
|
#warn "connecting to ($dsn|$user|$pass|$flags)\n";#d# |
134 |
root |
1.5 |
# first, nuke our statement cache (sooory ;) |
135 |
root |
1.1 |
cachesize cachesize 0; |
136 |
|
|
# then connect anew |
137 |
|
|
$dbcache{$id} = |
138 |
|
|
eval { DBI->connect($dsn, $user, $pass, $flags) } |
139 |
|
|
|| eval { DBI->connect($dsn, $user, $pass, $flags) } |
140 |
root |
1.5 |
|| die "unable to connect to database $dsn: $DBI::errstr\n"; |
141 |
root |
1.1 |
$connect->($dbcache{$id}) if $connect; |
142 |
|
|
} |
143 |
|
|
$dbcache{$id}; |
144 |
|
|
} |
145 |
|
|
|
146 |
|
|
=item $sth = sql_exec [dbh,] [bind-vals...,] "sql-statement", [arguments...] |
147 |
|
|
|
148 |
|
|
C<sql_exec> is the most important and most-used function in this module. |
149 |
|
|
|
150 |
|
|
Runs the given sql command with the given parameters and returns the |
151 |
|
|
statement handle. The command and the statement handle will be cached |
152 |
|
|
(with the database handle and the sql string as key), so prepare will be |
153 |
|
|
called only once for each distinct sql call (please keep in mind that the |
154 |
|
|
returned statement will always be the same, so, if you call C<sql_exec> |
155 |
|
|
with the same dbh and sql-statement twice (e.g. in a subroutine you |
156 |
|
|
called), the statement handle for the first call mustn't be used. |
157 |
|
|
|
158 |
|
|
The database handle (the first argument) is optional. If it is missing, |
159 |
|
|
C<sql_exec> first tries to use the variable C<$DBH> in the current (= |
160 |
|
|
calling) package and, if that fails, it tries to use database handle in |
161 |
|
|
C<$PApp::SQL::DBH>, which you can set before calling these functions. |
162 |
|
|
|
163 |
|
|
The actual return value from the C<$sth->execute> call is stored in the |
164 |
|
|
package-global (and exported) variable C<$sql_exec>. |
165 |
|
|
|
166 |
|
|
If any error occurs C<sql_exec> will throw an exception. |
167 |
|
|
|
168 |
|
|
Examples: |
169 |
|
|
|
170 |
|
|
# easy one |
171 |
|
|
my $st = sql_exec "select name, id from table where id = ?", $id; |
172 |
|
|
while (my ($name, $id) = $st->fetchrow_array) { ... }; |
173 |
|
|
|
174 |
|
|
# the fastest way to use dbi, using bind_columns |
175 |
|
|
my $st = sql_exec \my($name, $id), |
176 |
|
|
"select name, id from table where id = ?", |
177 |
|
|
$id; |
178 |
|
|
while ($st->fetch) { ...} |
179 |
|
|
|
180 |
|
|
# now use a different dastabase: |
181 |
|
|
sql_exec $dbh, "update file set name = ?", "oops.txt"; |
182 |
|
|
|
183 |
|
|
|
184 |
|
|
=item sql_fetch <see sql_exec> |
185 |
|
|
|
186 |
|
|
Execute a sql-statement and fetch the first row of results. Depending on |
187 |
|
|
the caller context the row will be returned as a list (array context), or |
188 |
|
|
just the first columns. In table form: |
189 |
|
|
|
190 |
|
|
CONTEXT RESULT |
191 |
|
|
void () |
192 |
|
|
scalar first column |
193 |
|
|
list array |
194 |
|
|
|
195 |
|
|
C<sql_fetch> is quite efficient in conjunction with bind variables: |
196 |
|
|
|
197 |
|
|
sql_fetch \my($name, $amount), |
198 |
|
|
"select name, amount from table where id name = ?", |
199 |
|
|
"Toytest"; |
200 |
|
|
|
201 |
|
|
But of course the normal way to call it is simply: |
202 |
|
|
|
203 |
|
|
my($name, $amount) = sql_fetch "select ...", args... |
204 |
|
|
|
205 |
|
|
... and it's still quite fast unless you fetch large amounts of data. |
206 |
|
|
|
207 |
|
|
=item sql_fetchall <see sql_exec> |
208 |
|
|
|
209 |
|
|
Similarly to C<sql_fetch>, but all result rows will be fetched (this is |
210 |
|
|
of course inefficient for large results!). The context is ignored (only |
211 |
|
|
list context makes sense), but the result still depends on the number of |
212 |
|
|
columns in the result: |
213 |
|
|
|
214 |
|
|
COLUMNS RESULT |
215 |
|
|
0 () |
216 |
|
|
1 (row1, row2, row3...) |
217 |
|
|
many ([row1], [row2], [row3]...) |
218 |
|
|
|
219 |
|
|
Examples (all of which are inefficient): |
220 |
|
|
|
221 |
|
|
for (sql_fetchall "select id from table") { ... } |
222 |
|
|
|
223 |
|
|
my @names = sql_fetchall "select name from user"; |
224 |
|
|
|
225 |
|
|
for (sql_fetchall "select name, age, place from user") { |
226 |
|
|
my ($name, $age, $place) = @$_; |
227 |
|
|
} |
228 |
|
|
|
229 |
|
|
=item sql_exists "<table> where ...", args... |
230 |
|
|
|
231 |
|
|
Check wether the result of the sql-statement "select xxx from |
232 |
|
|
$first_argument" would be empty or not (that is, imagine the string |
233 |
root |
1.13 |
"select * from" were prepended to your statement (it isn't)). Should work |
234 |
root |
1.1 |
with every database but can be quite slow, except on mysql, where this |
235 |
|
|
should be quite fast. |
236 |
|
|
|
237 |
|
|
Examples: |
238 |
|
|
|
239 |
|
|
print "user 7 exists!\n" |
240 |
|
|
if sql_exists "user where id = ?", 7; |
241 |
|
|
|
242 |
|
|
die "duplicate key" |
243 |
|
|
if sql_exists "user where name = ? and pass = ?", "stefan", "geheim"; |
244 |
|
|
|
245 |
|
|
=cut |
246 |
|
|
|
247 |
root |
1.3 |
=item $lastid = sql_insertid $sth |
248 |
|
|
|
249 |
root |
1.8 |
Returns the last automatically created key value. It must be executed |
250 |
|
|
directly after executing the insert statement that created it. This is |
251 |
|
|
what is actually returned for various databases. If your database is |
252 |
|
|
missing, please send me an e-mail on how to implement this ;) |
253 |
|
|
|
254 |
|
|
mysql: first C<AUTO_INCREMENT> column set to NULL |
255 |
|
|
postgres: C<oid> column (is there a way to get the last SERIAL?) |
256 |
|
|
sybase: C<IDENTITY> column of the last insert (slow) |
257 |
|
|
informix: C<SERIAL> or C<SERIAL8> column of the last insert |
258 |
|
|
|
259 |
|
|
Except for sybase, this does not require a server access. |
260 |
root |
1.3 |
|
261 |
|
|
=cut |
262 |
|
|
|
263 |
|
|
sub sql_insertid($) { |
264 |
|
|
my $sth = shift or die "sql_insertid requires a statement handle"; |
265 |
|
|
my $dbh = $sth->{Database}; |
266 |
|
|
my $driver = $dbh->{Driver}{Name}; |
267 |
|
|
|
268 |
root |
1.8 |
$driver eq "mysql" and return $sth->{mysql_insertid}; |
269 |
|
|
$driver eq "Pg" and return $sth->{pg_oid_status}; |
270 |
|
|
$driver eq "Sybase" and return sql_fetch($dbh, 'SELECT @@IDENTITY'); |
271 |
root |
1.3 |
$driver eq "Informix" and return $sth->{ix_sqlerrd}[1]; |
272 |
|
|
|
273 |
|
|
die "sql_insertid does not spport the dbd driver '$driver', please see PApp::SQL::sql_insertid"; |
274 |
root |
1.1 |
} |
275 |
|
|
|
276 |
|
|
=item [old-size] = cachesize [new-size] |
277 |
|
|
|
278 |
|
|
Returns (and possibly changes) the LRU cache size used by C<sql_exec>. The |
279 |
|
|
default is somewhere around 50 (= the 50 last recently used statements |
280 |
|
|
will be cached). It shouldn't be too large, since a simple linear listed |
281 |
|
|
is used for the cache at the moment (which, for small (<100) cache sizes |
282 |
|
|
is actually quite fast). |
283 |
|
|
|
284 |
|
|
The function always returns the cache size in effect I<before> the call, |
285 |
|
|
so, to nuke the cache (for example, when a database connection has died |
286 |
|
|
or you want to garbage collect old database/statement handles), this |
287 |
|
|
construct can be used: |
288 |
|
|
|
289 |
|
|
PApp::SQL::cachesize PApp::SQL::cachesize 0; |
290 |
|
|
|
291 |
|
|
=cut |
292 |
|
|
|
293 |
|
|
=item reinitialize [not exported] |
294 |
|
|
|
295 |
root |
1.9 |
Clears any internal caches (statement cache, database handle |
296 |
|
|
cache). Should be called after C<fork> and other accidents that invalidate |
297 |
|
|
database handles. |
298 |
root |
1.1 |
|
299 |
|
|
=cut |
300 |
|
|
|
301 |
|
|
sub reinitialize { |
302 |
|
|
cachesize cachesize 0; |
303 |
|
|
for (values %dbcache) { |
304 |
root |
1.11 |
eval { $_->{InactiveDestroy} = 1 }; |
305 |
root |
1.1 |
} |
306 |
|
|
undef %dbcache; |
307 |
|
|
} |
308 |
|
|
|
309 |
|
|
=back |
310 |
|
|
|
311 |
|
|
=cut |
312 |
|
|
|
313 |
root |
1.7 |
reinitialize; |
314 |
|
|
|
315 |
root |
1.1 |
package PApp::SQL::Database; |
316 |
|
|
|
317 |
|
|
=head2 THE DATABASE CLASS |
318 |
|
|
|
319 |
|
|
Again (sigh) the problem of persistency. What do you do when you have to serialize on object |
320 |
|
|
that contains (or should contain) a database handle? Short answer: you don't. Long answer: |
321 |
|
|
you can embed the necessary information to recreate the dbh when needed. |
322 |
|
|
|
323 |
|
|
The C<PApp::SQL::Database> class does that, in a relatively efficient |
324 |
|
|
fashion: the overhead is currently a single method call per access (you |
325 |
|
|
can cache the real dbh if you want). |
326 |
|
|
|
327 |
|
|
=over 4 |
328 |
|
|
|
329 |
|
|
=item $db = new <same arguments as C<connect_cached>> |
330 |
|
|
|
331 |
|
|
The C<new> call takes the same arguments as C<connect_cached> (obviously, |
332 |
|
|
if you supply a connect callback it better is serializable, see |
333 |
|
|
L<PApp::Callback>!) and returns a serializable database class. No database |
334 |
|
|
handle is actually being created. |
335 |
|
|
|
336 |
|
|
=item $db->dbh |
337 |
|
|
|
338 |
|
|
Return the database handle as fast as possible (usually just a hash lookup). |
339 |
|
|
|
340 |
|
|
=item $db->checked_dbh |
341 |
|
|
|
342 |
|
|
Return the database handle, but first check that the database is still |
343 |
|
|
available and re-open the connection if necessary. |
344 |
|
|
|
345 |
|
|
=cut |
346 |
|
|
|
347 |
|
|
sub new($$;@) { |
348 |
|
|
my $class = shift; |
349 |
|
|
my ($id, $dsn, $user, $pass, $flags, $connect) = @_; |
350 |
|
|
# the following line is duplicated in PApp::SQL::Database::new |
351 |
|
|
my $id2 = "$id\0$dsn\0$user\0$pass"; |
352 |
|
|
bless [$id2, $flags, $connect], $class; |
353 |
|
|
} |
354 |
|
|
|
355 |
|
|
# the following two functions better be fast! |
356 |
|
|
sub dbh($) { |
357 |
|
|
$dbcache{$_[0][0]} || $_[0]->checked_dbh; |
358 |
|
|
} |
359 |
|
|
|
360 |
|
|
sub checked_dbh($) { |
361 |
|
|
my $dbh = $dbcache{$_[0][0]}; |
362 |
|
|
$dbh && $dbh->ping |
363 |
|
|
? $dbh |
364 |
|
|
: PApp::SQL::connect_cached((split /\x00/, $_[0][0]), $_[0][1], $_[0][2]); |
365 |
|
|
} |
366 |
|
|
|
367 |
|
|
=item $db->dsn |
368 |
|
|
|
369 |
|
|
Return the DSN (L<DBI>) fo the database object (e.g. for error messages). |
370 |
|
|
|
371 |
|
|
=cut |
372 |
|
|
|
373 |
|
|
sub dsn($) { |
374 |
|
|
my $self = shift; |
375 |
root |
1.9 |
(split /\x00/, $self->[0])[1]; |
376 |
root |
1.1 |
} |
377 |
|
|
|
378 |
|
|
=back |
379 |
|
|
|
380 |
|
|
=cut |
381 |
|
|
|
382 |
|
|
1; |
383 |
|
|
|
384 |
|
|
=head1 SEE ALSO |
385 |
|
|
|
386 |
|
|
L<PApp>. |
387 |
|
|
|
388 |
|
|
=head1 AUTHOR |
389 |
|
|
|
390 |
|
|
Marc Lehmann <pcg@goof.com> |
391 |
|
|
http://www.goof.com/pcg/marc/ |
392 |
|
|
|
393 |
|
|
=cut |
394 |
|
|
|