[ViewVC] Diff of: cvs/PApp-SQL/SQL.pm

Comparing PApp-SQL/SQL.pm (file contents):
Revision 1.2 by root, Wed Nov 1 03:22:07 2000 UTC vs.
Revision 1.41 by root, Thu Apr 11 02:20:42 2013 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	PApp::SQL - absolutely easy yet fast and powerful sql access	3	PApp::SQL - absolutely easy yet fast and powerful sql access.
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use PApp::SQL;	7	use PApp::SQL;
8	# to be written	8
		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 $id = 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 "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 ...";
9		25
10	=head1 DESCRIPTION	26	=head1 DESCRIPTION
11		27
12	This module provides you with easy-to-use functions to execute sql	28	This module provides you with easy-to-use functions to execute sql
13	commands (using DBI). Despite being easy to use, they are also quite	29	commands (using DBI). Despite being easy to use, they are also quite
14	efficient and allow you to write faster programs in less lines of code.	30	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+. UTF8 handling (the C<sql_u*> family of functions) will only be
		33	effective with perl version 5.006 and beyond.
15		34
16	=over 4	35	If the descriptions here seem terse or if you always wanted to know
		36	what PApp is then have a look at the PApp module which uses this module
		37	extensively but also provides you with a lot more gimmicks to play around
		38	with to help you create cool applications ;)
17		39
18	=cut	40	=cut
19		41
20	package PApp::SQL;	42	package PApp::SQL;
21		43
		44	use Carp ();
22	use DBI;	45	use DBI ();
23
24	#use PApp::Exception; # not yet used
25		46
26	BEGIN {	47	BEGIN {
27	use base Exporter;	48	use base qw(Exporter DynaLoader);
28		49
29	$VERSION = 0.1;	50	$VERSION = '2.0';
30	@EXPORT = qw(	51	@EXPORT = qw(
31	sql_exec sql_fetch sql_fetchall sql_exists sql_insertid $sql_exec	52	sql_exec sql_fetch sql_fetchall sql_exists sql_insertid $sql_exec
		53	sql_uexec sql_ufetch sql_ufetchall sql_uexists
32	);	54	);
33	@EXPORT_OK = qw(	55	@EXPORT_OK = qw(
34	connect_cached	56	connect_cached
35	);	57	);
36		58
37	require XSLoader;	59	bootstrap PApp::SQL $VERSION;
38	XSLoader::load PApp::SQL, $VERSION;
39	}	60	}
		61
		62	boot2 DBI::SQL_VARCHAR, DBI::SQL_INTEGER, DBI::SQL_DOUBLE;
40		63
41	our $sql_exec; # last result of sql_exec's execute call	64	our $sql_exec; # last result of sql_exec's execute call
42	our $DBH; # the default database handle	65	our $DBH; # the default database handle
43	our $database; # the current SQL::Database object, if applicable	66	our $Database; # the current SQL::Database object, if applicable
44		67
45	our %dbcache;	68	our %dbcache;
		69
		70	=head2 Global Variables
		71
		72	=over 4
		73
		74	=item $sql_exec
		75
		76	Since the C<sql_exec> family of functions return a statement handle there
		77	must be another way to test the return value of the C<execute> call. This
		78	global variable contains the result of the most recent call to C<execute>
		79	done by this module.
		80
		81	=item $PApp::SQL::DBH
		82
		83	The default database handle used by this module if no C<$DBH> was
		84	specified as argument. See C<sql_exec> for a discussion.
		85
		86	=item $PApp::SQL::Database
		87
		88	The current default C<PApp::SQL::Database>-object. Future versions might
		89	automatically fall back on this database and create database handles from
		90	it if neccessary. At the moment this is not used by this module but might
		91	be nice as a placeholder for the database object that corresponds to
		92	$PApp::SQL::DBH.
		93
		94	=back
		95
		96	=head2 Functions
		97
		98	=over 4
46		99
47	=item $dbh = connect_cached $id, $dsn, $user, $pass, $flags, $connect	100	=item $dbh = connect_cached $id, $dsn, $user, $pass, $flags, $connect
48		101
49	(not exported by by default)	102	(not exported by by default)
50		103
51	Connect to the database given by C<($dsn,$user,$pass)>, while using the	104	Connect to the database given by C<($dsn,$user,$pass)>, while using the
52	flags from C<$flags>. These are just the same arguments as given to	105	flags from C<$flags>. These are just the same arguments as given to
53	C<DBI->connect>.	106	C<< DBI->connect >>.
54		107
55	The database handle will be cached under the unique id C<$id>. If the same	108	The database handle will be cached under the unique id
56	id is requested later, the cached handle will be checked (using ping), and	109	C<$id\|$dsn\|$user\|$pass>. If the same id is requested later, the
		110	cached handle will be checked (using ping), and the connection will
57	the connection will be re-established if necessary (be sure to prefix your	111	be re-established if necessary (be sure to prefix your application or
58	application or module name to the id to make it "more" unique. Things like	112	module name to the id to make it "more" unique. Things like __PACKAGE__ .
59	__PACKAGE__ . __LINE__ work fine as well).	113	__LINE__ work fine as well).
		114
		115	The reason C<$id> is necessary is that you might specify special connect
		116	arguments or special flags, or you might want to configure your $DBH
		117	differently than maybe other applications requesting the same database
		118	connection. If none of this is necessary for your application you can
		119	leave C<$id> empty (i.e. "").
60		120
61	If specified, C<$connect> is a callback (e.g. a coderef) that will be	121	If specified, C<$connect> is a callback (e.g. a coderef) that will be
62	called each time a new connection is being established, with the new	122	called each time a new connection is being established, with the new
63	C<$dbh> as first argument.	123	C<$dbh> as first argument.
64		124
65	Examples:	125	Examples:
66		126
67	# try your luck opening the papp database without access info	127	# try your luck opening the papp database without access info
68	$dbh = connect_cached __FILE__, "DBI:mysql:papp";	128	$dbh = connect_cached __FILE__, "DBI:mysql:papp";
		129
		130	Mysql-specific behaviour: The default setting of
		131	C<mysql_client_found_rows> is TRUE, you can overwrite this, though.
69		132
70	=cut	133	=cut
71		134
72	sub connect_cached {	135	sub connect_cached {
73	my ($id, $dsn, $user, $pass, $flags, $connect) = @_;	136	my ($id, $dsn, $user, $pass, $flags, $connect) = @_;
74	# the following line is duplicated in PApp::SQL::Database::new	137	# the following line is duplicated in PApp::SQL::Database::new
75	$id = "$id\0$dsn\0$user\0$pass";	138	$id = "$id\0$dsn\0$user\0$pass";
76	unless ($dbcache{$id} && $dbcache{$id}->ping) {	139	unless ($dbcache{$id} && $dbcache{$id}->ping) {
77	#warn "connecting to ($dsn\|$user\|$pass\|$flags)\n";#d#
78	# first, nuke our cache (sooory ;)	140	# first, nuke our statement cache (sooory ;)
79	cachesize cachesize 0;	141	cachesize cachesize 0;
		142
		143	# then make mysql behave more standardly by default
		144	$dsn =~ /^[Dd][Bb][Ii]:mysql:/
		145	and $dsn !~ /;mysql_client_found_rows/
		146	and $dsn .= ";mysql_client_found_rows=1";
		147
80	# then connect anew	148	# then connect anew
81	$dbcache{$id} =	149	$dbcache{$id} =
82	eval { DBI->connect($dsn, $user, $pass, $flags) }	150	eval { DBI->connect($dsn, $user, $pass, $flags) }
83	\|\| eval { DBI->connect($dsn, $user, $pass, $flags) }	151	\|\| eval { DBI->connect($dsn, $user, $pass, $flags) }
84	\|\| die "$DBI::errstr\n";	152	\|\| Carp::croak "unable to connect to database $dsn: $DBI::errstr\n";
85	$connect->($dbcache{$id}) if $connect;	153	$connect->($dbcache{$id}) if $connect;
86	}	154	}
87	$dbcache{$id};	155	$dbcache{$id};
88	}	156	}
89		157
90	=item $sth = sql_exec [dbh,] [bind-vals...,] "sql-statement", [arguments...]	158	=item $sth = sql_exec [dbh,] [bind-vals...,] "sql-statement", [arguments...]
		159
		160	=item $sth = sql_uexec <see sql_exec>
91		161
92	C<sql_exec> is the most important and most-used function in this module.	162	C<sql_exec> is the most important and most-used function in this module.
93		163
94	Runs the given sql command with the given parameters and returns the	164	Runs the given sql command with the given parameters and returns the
95	statement handle. The command and the statement handle will be cached	165	statement handle. The command and the statement handle will be cached
96	(with the database handle and the sql string as key), so prepare will be	166	(with the database handle and the sql string as key), so prepare will be
97	called only once for each distinct sql call (please keep in mind that the	167	called only once for each distinct sql call (please keep in mind that the
98	returned statement will always be the same, so, if you call C<sql_exec>	168	returned statement will always be the same, so, if you call C<sql_exec>
99	with the same dbh and sql-statement twice (e.g. in a subroutine you	169	with the same dbh and sql-statement twice (e.g. in a subroutine you
100	called), the statement handle for the first call mustn't be used.	170	called), the statement handle for the first call mustn't not be in use
		171	anymore, as the subsequent call will re-use the handle.
101		172
102	The database handle (the first argument) is optional. If it is missing,	173	The database handle (the first argument) is optional. If it is missing,
103	C<sql_exec> first tries to use the variable C<$DBH> in the current (=	174	it tries to use database handle in C<$PApp::SQL::DBH>, which you can set
104	calling) package and, if that fails, it tries to use database handle in	175	before calling these functions. NOTICE: future and former versions of
105	C<$PApp::SQL::DBH>, which you can set before calling these functions.	176	PApp::SQL might also look up the global variable C<$DBH> in the callers
		177	package.
106		178
		179	=begin comment
		180
		181	If it is missing, C<sql_exec> first tries to use the variable C<$DBH>
		182	in the current (= calling) package and, if that fails, it tries to use
		183	database handle in C<$PApp::SQL::DBH>, which you can set before calling
		184	these functions.
		185
		186	=end comment
		187
107	The actual return value from the C<$sth->execute> call is stored in the	188	The actual return value from the C<< $sth->execute >> call is stored in
108	package-global (and exported) variable C<$sql_exec>.	189	the package-global (and exported) variable C<$sql_exec>.
109		190
110	If any error occurs C<sql_exec> will throw an exception.	191	If any error occurs C<sql_exec> will throw an exception.
		192
		193	C<sql_uexec> is similar to C<sql_exec> but upgrades all input arguments to
		194	UTF-8 before calling the C<execute> method.
111		195
112	Examples:	196	Examples:
113		197
114	# easy one	198	# easy one
115	my $st = sql_exec "select name, id from table where id = ?", $id;	199	my $st = sql_exec "select name, id from table where id = ?", $id;
125	sql_exec $dbh, "update file set name = ?", "oops.txt";	209	sql_exec $dbh, "update file set name = ?", "oops.txt";
126		210
127		211
128	=item sql_fetch <see sql_exec>	212	=item sql_fetch <see sql_exec>
129		213
		214	=item sql_ufetch <see sql_uexec>
		215
130	Execute a sql-statement and fetch the first row of results. Depending on	216	Execute an sql-statement and fetch the first row of results. Depending on
131	the caller context the row will be returned as a list (array context), or	217	the caller context the row will be returned as a list (array context), or
132	just the first columns. In table form:	218	just the first columns. In table form:
133		219
134	CONTEXT RESULT	220	CONTEXT RESULT
135	void ()	221	void ()
…		…
146		232
147	my($name, $amount) = sql_fetch "select ...", args...	233	my($name, $amount) = sql_fetch "select ...", args...
148		234
149	... and it's still quite fast unless you fetch large amounts of data.	235	... and it's still quite fast unless you fetch large amounts of data.
150		236
		237	C<sql_ufetch> is similar to C<sql_fetch> but upgrades all input values to
		238	UTF-8 and forces all result values to UTF-8 (this does I<not> include result
		239	parameters, only return values. Using bind variables in conjunction with
		240	sql_u* functions might result in undefined behaviour - we use UTF-8 on
		241	bind-variables at execution time and it seems to work on DBD::mysql as it
		242	ignores the UTF-8 bit completely. Which just means that that DBD-driver is
		243	broken).
		244
151	=item sql_fetchall <see sql_exec>	245	=item sql_fetchall <see sql_exec>
		246
		247	=item sql_ufetchall <see sql_uexec>
152		248
153	Similarly to C<sql_fetch>, but all result rows will be fetched (this is	249	Similarly to C<sql_fetch>, but all result rows will be fetched (this is
154	of course inefficient for large results!). The context is ignored (only	250	of course inefficient for large results!). The context is ignored (only
155	list context makes sense), but the result still depends on the number of	251	list context makes sense), but the result still depends on the number of
156	columns in the result:	252	columns in the result:
…		…
168		264
169	for (sql_fetchall "select name, age, place from user") {	265	for (sql_fetchall "select name, age, place from user") {
170	my ($name, $age, $place) = @$_;	266	my ($name, $age, $place) = @$_;
171	}	267	}
172		268
		269	C<sql_ufetchall> is similar to C<sql_fetchall> but upgrades all input
		270	values to UTF-8 and forces all result values to UTF-8 (see the caveats in
		271	the description of C<sql_ufetch>, though).
		272
173	=item sql_exists "<table> where ...", args...	273	=item sql_exists "<table_references> where <where_condition>...", args...
		274
		275	=item sql_uexists <see sql_exists>
174		276
175	Check wether the result of the sql-statement "select xxx from	277	Check wether the result of the sql-statement "select xxx from
176	$first_argument" would be empty or not (that is, imagine the string	278	$first_argument" would be empty or not (that is, imagine the string
177	"select from" were prepended to your statement (it isn't)). Should work	279	"select * from" were prepended to your statement (it isn't)). Should work
178	with every database but can be quite slow, except on mysql, where this	280	with every database but can be quite slow, except on mysql, where this
179	should be quite fast.	281	should be quite fast.
		282
		283	C<sql_uexists> is similar to C<sql_exists> but upgrades all parameters to
		284	UTF-8.
180		285
181	Examples:	286	Examples:
182		287
183	print "user 7 exists!\n"	288	print "user 7 exists!\n"
184	if sql_exists "user where id = ?", 7;	289	if sql_exists "user where id = ?", 7;
…		…
186	die "duplicate key"	291	die "duplicate key"
187	if sql_exists "user where name = ? and pass = ?", "stefan", "geheim";	292	if sql_exists "user where name = ? and pass = ?", "stefan", "geheim";
188		293
189	=cut	294	=cut
190		295
191	# uncodumented, since unportable (only works with DBH even!). yet it is exported (aaargh!)	296	=item $lastid = sql_insertid $sth
		297
		298	Returns the last automatically created key value. It must be executed
		299	directly after executing the insert statement that created it. This is
		300	what is actually returned for various databases. If your database is
		301	missing, please send me an e-mail on how to implement this ;)
		302
		303	mysql: first C<AUTO_INCREMENT> column set to NULL
		304	postgres: C<oid> column (is there a way to get the last SERIAL?)
		305	sybase: C<IDENTITY> column of the last insert (slow)
		306	informix: C<SERIAL> or C<SERIAL8> column of the last insert
		307	sqlite: C<last_insert_rowid()>
		308
		309	Except for sybase, this does not require a server access.
		310
		311	=cut
		312
192	sub sql_insertid {	313	sub sql_insertid($) {
193	$DBH->{mysql_insertid};	314	my $sth = shift or Carp::croak "sql_insertid requires a statement handle";
		315	my $dbh = $sth->{Database};
		316	my $driver = $dbh->{Driver}{Name};
		317
		318	$driver eq "mysql" and return $sth->{mysql_insertid};
		319	$driver eq "Pg" and return $sth->{pg_oid_status};
		320	$driver eq "Sybase" and return sql_fetch ($dbh, 'SELECT @@IDENTITY');
		321	$driver eq "Informix" and return $sth->{ix_sqlerrd}[1];
		322	$driver eq "SQLite" and return sql_fetch ($dbh, 'SELECT last_insert_rowid ()');
		323
		324	Carp::croak "sql_insertid does not support the dbd driver '$driver', at";
194	}	325	}
195		326
196	=item [old-size] = cachesize [new-size]	327	=item [old-size] = cachesize [new-size]
197		328
198	Returns (and possibly changes) the LRU cache size used by C<sql_exec>. The	329	Returns (and possibly changes) the LRU cache size used by C<sql_exec>. The
199	default is somewhere around 50 (= the 50 last recently used statements	330	default is somewhere around 50 (= the 50 last recently used statements
200	will be cached). It shouldn't be too large, since a simple linear listed	331	will be cached). It shouldn't be too large, since a simple linear list
201	is used for the cache at the moment (which, for small (<100) cache sizes	332	is used for the cache at the moment (which, for small (<100) cache sizes
202	is actually quite fast).	333	is actually quite fast).
203		334
204	The function always returns the cache size in effect I<before> the call,	335	The function always returns the cache size in effect I<before> the call,
205	so, to nuke the cache (for example, when a database connection has died	336	so, to nuke the cache (for example, when a database connection has died
…		…
210		341
211	=cut	342	=cut
212		343
213	=item reinitialize [not exported]	344	=item reinitialize [not exported]
214		345
215	Clears any internal caches (statement cache, database handle cache).	346	Clears any internal caches (statement cache, database handle
		347	cache). Should be called after C<fork> and other accidents that invalidate
		348	database handles.
216		349
217	=cut	350	=cut
218		351
219	sub reinitialize {	352	sub reinitialize {
220	cachesize cachesize 0;	353	cachesize cachesize 0;
221	for (values %dbcache) {	354	for (values %dbcache) {
222	eval { $_->disconnect };	355	eval { $_->{InactiveDestroy} = 1 };
223	}	356	}
224	undef %dbcache;	357	undef %dbcache;
225	}	358	}
226		359
227	=back	360	=back
228		361
229	=cut	362	=cut
230		363
		364	reinitialize;
		365
		366	=head2 Type Deduction
		367
		368	Since every database driver seems to deduce parameter types differently,
		369	usually wrongly, and at leats in the case of DBD::mysql, different in
		370	every other release or so, and this can and does lead to data corruption,
		371	this module does type deduction itself.
		372
		373	What does it mean? Simple - sql parameters for placeholders will be
		374	explicitly marked as SQL_VARCHAR, SQL_INTEGER or SQL_DOUBLE the first time
		375	a statement is prepared.
		376
		377	To force a specific type, you can either continue to use e.g. sql casts,
		378	or you can make sure to consistently use strings or numbers. To make a
		379	perl scalar look enough like a string or a number, use this when passing
		380	it to sql_exec or a similar functions:
		381
		382	"$string" # to pass a string
		383	$num+0 # to pass a number
		384
		385	=cut
		386
231	package PApp::SQL::Database;	387	package PApp::SQL::Database;
232		388
233	=head2 THE DATABASE CLASS	389	=head2 The Database Class
234		390
235	Again (sigh) the problem of persistency. What do you do when you have to serialize on object	391	Again (sigh) the problem of persistency. What do you do when you have
236	that contains (or should contain) a database handle? Short answer: you don't. Long answer:	392	to serialize on object that contains (or should contain) a database
		393	handle? Short answer: you don't. Long answer: you can embed the necessary
237	you can embed the necessary information to recreate the dbh when needed.	394	information to recreate the dbh when needed.
238		395
239	The C<PApp::SQL::Database> class does that, in a relatively efficient	396	The C<PApp::SQL::Database> class does that, in a relatively efficient
240	fashion: the overhead is currently a single method call per access (you	397	fashion: the overhead is currently a single method call per access (you
241	can cache the real dbh if you want).	398	can cache the real dbh if you want).
242		399
…		…
275		432
276	sub checked_dbh($) {	433	sub checked_dbh($) {
277	my $dbh = $dbcache{$_[0][0]};	434	my $dbh = $dbcache{$_[0][0]};
278	$dbh && $dbh->ping	435	$dbh && $dbh->ping
279	? $dbh	436	? $dbh
280	: PApp::SQL::connect_cached((split /\x00/, $_[0][0]), $_[0][1], $_[0][2]);	437	: PApp::SQL::connect_cached((split /\x00/, $_[0][0], 4), $_[0][1], $_[0][2]);
281	}	438	}
282		439
283	=item $db->dsn	440	=item $db->dsn
284		441
285	Return the DSN (L<DBI>) fo the database object (e.g. for error messages).	442	Return the DSN (L<DBI>) fo the database object (e.g. for error messages).
		443
		444	=item $db->login
		445
		446	Return the login name.
		447
		448	=item $db->password
		449
		450	Return the password (emphasizing the fact that the password is stored plaintext ;)
286		451
287	=cut	452	=cut
288		453
289	sub dsn($) {	454	sub dsn($) {
290	my $self = shift;	455	my $self = shift;
291	$self->[1][1];	456	(split /\x00/, $self->[0])[1];
		457	}
		458
		459	sub login($) {
		460	my $self = shift;
		461	(split /\x00/, $self->[0])[2];
		462	}
		463
		464	sub password($) {
		465	my $self = shift;
		466	(split /\x00/, $self->[0])[3];
292	}	467	}
293		468
294	=back	469	=back
295		470
296	=cut	471	=cut
297		472
298	reinitialize;
299
300	1;	473	1;
301		474
302	=head1 BUGS
303
304	As of this writing, sql_fetch and sql_fetchall are not very well tested
305	(they were just re-written in C).
306
307	sql_exists could be faster (it is written very ugly to not change the
308	current package).
309
310	=head1 SEE ALSO	475	=head1 SEE ALSO
311		476
312	L<PApp>.	477	L<PApp>.
313		478
314	=head1 AUTHOR	479	=head1 AUTHOR
315		480
316	Marc Lehmann <pcg@goof.com>	481	Marc Lehmann <schmorp@schmorp.de>
317	http://www.goof.com/pcg/marc/	482	http://home.schmorp.de/
318		483
319	=cut	484	=cut
320		485

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Comparing PApp-SQL/SQL.pm (file contents): Revision 1.2 by root, Wed Nov 1 03:22:07 2000 UTC vs. Revision 1.41 by root, Thu Apr 11 02:20:42 2013 UTC

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Comparing PApp-SQL/SQL.pm (file contents):
Revision 1.2 by root, Wed Nov 1 03:22:07 2000 UTC vs.
Revision 1.41 by root, Thu Apr 11 02:20:42 2013 UTC