1DBIx::Class::Storage::DUBsIe(r3)Contributed Perl DocumenDtBaItxi:o:nClass::Storage::DBI(3)
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3
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NAME

6       DBIx::Class::Storage::DBI - DBI storage handler
7

SYNOPSIS

9         my $schema = MySchema->connect('dbi:SQLite:my.db');
10
11         $schema->storage->debug(1);
12
13         my @stuff = $schema->storage->dbh_do(
14           sub {
15             my ($storage, $dbh, @args) = @_;
16             $dbh->do("DROP TABLE authors");
17           },
18           @column_list
19         );
20
21         $schema->resultset('Book')->search({
22            written_on => $schema->storage->datetime_parser->format_datetime(DateTime->now)
23         });
24

DESCRIPTION

26       This class represents the connection to an RDBMS via DBI.  See
27       DBIx::Class::Storage for general information.  This pod only documents
28       DBI-specific methods and behaviors.
29

METHODS

31   connect_info
32       This method is normally called by "connection" in DBIx::Class::Schema,
33       which encapsulates its argument list in an arrayref before passing them
34       here.
35
36       The argument list may contain:
37
38       •   The same 4-element argument set one would normally pass to
39           "connect" in DBI, optionally followed by extra attributes
40           recognized by DBIx::Class:
41
42             $connect_info_args = [ $dsn, $user, $password, \%dbi_attributes?, \%extra_attributes? ];
43
44       •   A single code reference which returns a connected DBI database
45           handle optionally followed by extra attributes recognized by
46           DBIx::Class:
47
48             $connect_info_args = [ sub { DBI->connect (...) }, \%extra_attributes? ];
49
50       •   A single hashref with all the attributes and the dsn/user/password
51           mixed together:
52
53             $connect_info_args = [{
54               dsn => $dsn,
55               user => $user,
56               password => $pass,
57               %dbi_attributes,
58               %extra_attributes,
59             }];
60
61             $connect_info_args = [{
62               dbh_maker => sub { DBI->connect (...) },
63               %dbi_attributes,
64               %extra_attributes,
65             }];
66
67           This is particularly useful for Catalyst based applications,
68           allowing the following config (Config::General style):
69
70             <Model::DB>
71               schema_class   App::DB
72               <connect_info>
73                 dsn          dbi:mysql:database=test
74                 user         testuser
75                 password     TestPass
76                 AutoCommit   1
77               </connect_info>
78             </Model::DB>
79
80           The "dsn"/"user"/"password" combination can be substituted by the
81           "dbh_maker" key whose value is a coderef that returns a connected
82           DBI database handle
83
84       Please note that the DBI docs recommend that you always explicitly set
85       "AutoCommit" to either 0 or 1.  DBIx::Class further recommends that it
86       be set to 1, and that you perform transactions via our "txn_do" in
87       DBIx::Class::Schema method.  DBIx::Class will set it to 1 if you do not
88       do explicitly set it to zero.  This is the default for most DBDs. See
89       "DBIx::Class and AutoCommit" for details.
90
91       DBIx::Class specific connection attributes
92
93       In addition to the standard DBI connection attributes, DBIx::Class
94       recognizes the following connection options. These options can be mixed
95       in with your other DBI connection attributes, or placed in a separate
96       hashref ("\%extra_attributes") as shown above.
97
98       Every time "connect_info" is invoked, any previous settings for these
99       options will be cleared before setting the new ones, regardless of
100       whether any options are specified in the new "connect_info".
101
102       on_connect_do
103           Specifies things to do immediately after connecting or re-
104           connecting to the database.  Its value may contain:
105
106           a scalar
107               This contains one SQL statement to execute.
108
109           an array reference
110               This contains SQL statements to execute in order.  Each element
111               contains a string or a code reference that returns a string.
112
113           a code reference
114               This contains some code to execute.  Unlike code references
115               within an array reference, its return value is ignored.
116
117       on_disconnect_do
118           Takes arguments in the same form as "on_connect_do" and executes
119           them immediately before disconnecting from the database.
120
121           Note, this only runs if you explicitly call "disconnect" on the
122           storage object.
123
124       on_connect_call
125           A more generalized form of "on_connect_do" that calls the specified
126           "connect_call_METHOD" methods in your storage driver.
127
128             on_connect_do => 'select 1'
129
130           is equivalent to:
131
132             on_connect_call => [ [ do_sql => 'select 1' ] ]
133
134           Its values may contain:
135
136           a scalar
137               Will call the "connect_call_METHOD" method.
138
139           a code reference
140               Will execute "$code->($storage)"
141
142           an array reference
143               Each value can be a method name or code reference.
144
145           an array of arrays
146               For each array, the first item is taken to be the
147               "connect_call_" method name or code reference, and the rest are
148               parameters to it.
149
150           Some predefined storage methods you may use:
151
152           do_sql
153               Executes a SQL string or a code reference that returns a SQL
154               string. This is what "on_connect_do" and "on_disconnect_do"
155               use.
156
157               It can take:
158
159               a scalar
160                   Will execute the scalar as SQL.
161
162               an arrayref
163                   Taken to be arguments to "do" in DBI, the SQL string
164                   optionally followed by the attributes hashref and bind
165                   values.
166
167               a code reference
168                   Will execute "$code->($storage)" and execute the return
169                   array refs as above.
170
171           datetime_setup
172               Execute any statements necessary to initialize the database
173               session to return and accept datetime/timestamp values used
174               with DBIx::Class::InflateColumn::DateTime.
175
176               Only necessary for some databases, see your specific storage
177               driver for implementation details.
178
179       on_disconnect_call
180           Takes arguments in the same form as "on_connect_call" and executes
181           them immediately before disconnecting from the database.
182
183           Calls the "disconnect_call_METHOD" methods as opposed to the
184           "connect_call_METHOD" methods called by "on_connect_call".
185
186           Note, this only runs if you explicitly call "disconnect" on the
187           storage object.
188
189       disable_sth_caching
190           If set to a true value, this option will disable the caching of
191           statement handles via "prepare_cached" in DBI.
192
193       limit_dialect
194           Sets a specific SQL::Abstract::Limit-style limit dialect,
195           overriding the default "sql_limit_dialect" setting of the storage
196           (if any). For a list of available limit dialects see
197           DBIx::Class::SQLMaker::LimitDialects.
198
199       quote_names
200           When true automatically sets "quote_char" and "name_sep" to the
201           characters appropriate for your particular RDBMS. This option is
202           preferred over specifying "quote_char" directly.
203
204       quote_char
205           Specifies what characters to use to quote table and column names.
206
207           "quote_char" expects either a single character, in which case is it
208           is placed on either side of the table/column name, or an arrayref
209           of length 2 in which case the table/column name is placed between
210           the elements.
211
212           For example under MySQL you should use "quote_char => '`'", and for
213           SQL Server you should use "quote_char => [qw/[ ]/]".
214
215       name_sep
216           This parameter is only useful in conjunction with "quote_char", and
217           is used to specify the character that separates elements (schemas,
218           tables, columns) from each other. If unspecified it defaults to the
219           most commonly used ".".
220
221       unsafe
222           This Storage driver normally installs its own "HandleError", sets
223           "RaiseError" and "ShowErrorStatement" on, and sets "PrintError" off
224           on all database handles, including those supplied by a coderef.  It
225           does this so that it can have consistent and useful error behavior.
226
227           If you set this option to a true value, Storage will not do its
228           usual modifications to the database handle's attributes, and
229           instead relies on the settings in your connect_info DBI options (or
230           the values you set in your connection coderef, in the case that you
231           are connecting via coderef).
232
233           Note that your custom settings can cause Storage to malfunction,
234           especially if you set a "HandleError" handler that suppresses
235           exceptions and/or disable "RaiseError".
236
237       auto_savepoint
238           If this option is true, DBIx::Class will use savepoints when
239           nesting transactions, making it possible to recover from failure in
240           the inner transaction without having to abort all outer
241           transactions.
242
243       cursor_class
244           Use this argument to supply a cursor class other than the default
245           DBIx::Class::Storage::DBI::Cursor.
246
247       Some real-life examples of arguments to "connect_info" and "connect" in
248       DBIx::Class::Schema
249
250         # Simple SQLite connection
251         ->connect_info([ 'dbi:SQLite:./foo.db' ]);
252
253         # Connect via subref
254         ->connect_info([ sub { DBI->connect(...) } ]);
255
256         # Connect via subref in hashref
257         ->connect_info([{
258           dbh_maker => sub { DBI->connect(...) },
259           on_connect_do => 'alter session ...',
260         }]);
261
262         # A bit more complicated
263         ->connect_info(
264           [
265             'dbi:Pg:dbname=foo',
266             'postgres',
267             'my_pg_password',
268             { AutoCommit => 1 },
269             { quote_char => q{"} },
270           ]
271         );
272
273         # Equivalent to the previous example
274         ->connect_info(
275           [
276             'dbi:Pg:dbname=foo',
277             'postgres',
278             'my_pg_password',
279             { AutoCommit => 1, quote_char => q{"}, name_sep => q{.} },
280           ]
281         );
282
283         # Same, but with hashref as argument
284         # See parse_connect_info for explanation
285         ->connect_info(
286           [{
287             dsn         => 'dbi:Pg:dbname=foo',
288             user        => 'postgres',
289             password    => 'my_pg_password',
290             AutoCommit  => 1,
291             quote_char  => q{"},
292             name_sep    => q{.},
293           }]
294         );
295
296         # Subref + DBIx::Class-specific connection options
297         ->connect_info(
298           [
299             sub { DBI->connect(...) },
300             {
301                 quote_char => q{`},
302                 name_sep => q{@},
303                 on_connect_do => ['SET search_path TO myschema,otherschema,public'],
304                 disable_sth_caching => 1,
305             },
306           ]
307         );
308
309   on_connect_do
310       This method is deprecated in favour of setting via "connect_info".
311
312   on_disconnect_do
313       This method is deprecated in favour of setting via "connect_info".
314
315   dbh_do
316       Arguments: ($subref | $method_name), @extra_coderef_args?
317
318       Execute the given $subref or $method_name using the new exception-based
319       connection management.
320
321       The first two arguments will be the storage object that "dbh_do" was
322       called on and a database handle to use.  Any additional arguments will
323       be passed verbatim to the called subref as arguments 2 and onwards.
324
325       Using this (instead of $self->_dbh or $self->dbh) ensures correct
326       exception handling and reconnection (or failover in future subclasses).
327
328       Your subref should have no side-effects outside of the database, as
329       there is the potential for your subref to be partially double-executed
330       if the database connection was stale/dysfunctional.
331
332       Example:
333
334         my @stuff = $schema->storage->dbh_do(
335           sub {
336             my ($storage, $dbh, @cols) = @_;
337             my $cols = join(q{, }, @cols);
338             $dbh->selectrow_array("SELECT $cols FROM foo");
339           },
340           @column_list
341         );
342
343   disconnect
344       Our "disconnect" method also performs a rollback first if the database
345       is not in "AutoCommit" mode.
346
347   with_deferred_fk_checks
348       Arguments: $coderef
349       Return Value: The return value of $coderef
350
351       Storage specific method to run the code ref with FK checks deferred or
352       in MySQL's case disabled entirely.
353
354   connected
355       Arguments: none
356       Return Value: 1|0
357
358       Verifies that the current database handle is active and ready to
359       execute an SQL statement (e.g. the connection did not get stale, server
360       is still answering, etc.) This method is used internally by "dbh".
361
362   dbh
363       Returns a $dbh - a data base handle of class DBI. The returned handle
364       is guaranteed to be healthy by implicitly calling "connected", and if
365       necessary performing a reconnection before returning. Keep in mind that
366       this is very expensive on some database engines. Consider using
367       "dbh_do" instead.
368
369   connect_call_datetime_setup
370       A no-op stub method, provided so that one can always safely supply the
371       connection option
372
373        on_connect_call => 'datetime_setup'
374
375       This way one does not need to know in advance whether the underlying
376       storage requires any sort of hand-holding when dealing with calendar
377       data.
378
379   connect_call_rebase_sqlmaker
380       This on-connect call takes as a single argument the name of a class to
381       "rebase" the SQLMaker inheritance hierarchy upon. For this to work
382       properly the target class MUST inherit from
383       DBIx::Class::SQLMaker::ClassicExtensions and SQL::Abstract::Classic as
384       shown below.
385
386       This infrastructure is provided to aid recent activity around
387       experimental new aproaches to SQL generation within DBIx::Class. You
388       can (and are encouraged to) mix and match old and new within the same
389       codebase as follows:
390
391         package DBIx::Class::Awesomer::SQLMaker;
392         # you MUST inherit in this order to get the composition right
393         # you are free to override-without-next::method any part you need
394         use base qw(
395           DBIx::Class::SQLMaker::ClassicExtensions
396           << OPTIONAL::AWESOME::Class::Implementing::ExtraRainbowSauce >>
397           SQL::Abstract::Classic
398         );
399         << your new code goes here >>
400
401
402         ... and then ...
403
404
405         my $experimental_schema = $original_schema->connect(
406           sub {
407             $original_schema->storage->dbh
408           },
409           {
410             # the nested arrayref is important, as per
411             # https://metacpan.org/pod/DBIx::Class::Storage::DBI#on_connect_call
412             on_connect_call => [ [ rebase_sqlmaker => 'DBIx::Class::Awesomer::SQLMaker' ] ],
413           },
414         );
415
416   select
417       Arguments: $ident, $select, $condition, $attrs
418
419       Handle a SQL select statement.
420
421   sql_limit_dialect
422       This is an accessor for the default SQL limit dialect used by a
423       particular storage driver. Can be overridden by supplying an explicit
424       "limit_dialect" to "connect" in DBIx::Class::Schema. For a list of
425       available limit dialects see DBIx::Class::SQLMaker::LimitDialects.
426
427   last_insert_id
428       Return the row id of the last insert.
429
430   _native_data_type
431       Arguments: $type_name
432
433       This API is EXPERIMENTAL, will almost definitely change in the future,
434       and currently only used by ::AutoCast and ::Sybase::ASE.
435
436       The default implementation returns "undef", implement in your Storage
437       driver if you need this functionality.
438
439       Should map types from other databases to the native RDBMS type, for
440       example "VARCHAR2" to "VARCHAR".
441
442       Types with modifiers should map to the underlying data type. For
443       example, "INTEGER AUTO_INCREMENT" should become "INTEGER".
444
445       Composite types should map to the container type, for example
446       "ENUM(foo,bar,baz)" becomes "ENUM".
447
448   sqlt_type
449       Returns the database driver name.
450
451   bind_attribute_by_data_type
452       Given a datatype from column info, returns a database specific bind
453       attribute for "$dbh->bind_param($val,$attribute)" or nothing if we will
454       let the database planner just handle it.
455
456       This method is always called after the driver has been determined and a
457       DBI connection has been established. Therefore you can refer to
458       "DBI::$constant" and/or "DBD::$driver::$constant" directly, without
459       worrying about loading the correct modules.
460
461   is_datatype_numeric
462       Given a datatype from column_info, returns a boolean value indicating
463       if the current RDBMS considers it a numeric value. This controls how
464       "set_column" in DBIx::Class::Row decides whether to mark the column as
465       dirty - when the datatype is deemed numeric a "!=" comparison will be
466       performed instead of the usual "eq".
467
468   create_ddl_dir
469       Arguments: $schema, \@databases, $version, $directory, $preversion,
470       \%sqlt_args
471
472       Creates a SQL file based on the Schema, for each of the specified
473       database engines in "\@databases" in the given directory.  (note:
474       specify SQL::Translator names, not DBI driver names).
475
476       Given a previous version number, this will also create a file
477       containing the ALTER TABLE statements to transform the previous schema
478       into the current one. Note that these statements may contain "DROP
479       TABLE" or "DROP COLUMN" statements that can potentially destroy data.
480
481       The file names are created using the "ddl_filename" method below,
482       please override this method in your schema if you would like a
483       different file name format. For the ALTER file, the same format is
484       used, replacing $version in the name with "$preversion-$version".
485
486       See "METHODS" in SQL::Translator for a list of values for
487       "\%sqlt_args".  The most common value for this would be "{
488       add_drop_table => 1 }" to have the SQL produced include a "DROP TABLE"
489       statement for each table created. For quoting purposes supply
490       "quote_identifiers".
491
492       If no arguments are passed, then the following default values are
493       assumed:
494
495       databases  - ['MySQL', 'SQLite', 'PostgreSQL']
496       version    - $schema->schema_version
497       directory  - './'
498       preversion - <none>
499
500       By default, "\%sqlt_args" will have
501
502        { add_drop_table => 1, ignore_constraint_names => 1, ignore_index_names => 1 }
503
504       merged with the hash passed in. To disable any of those features, pass
505       in a hashref like the following
506
507        { ignore_constraint_names => 0, # ... other options }
508
509       WARNING: You are strongly advised to check all SQL files created,
510       before applying them.
511
512   deployment_statements
513       Arguments: $schema, $type, $version, $directory, $sqlt_args
514
515       Returns the statements used by "deploy" in DBIx::Class::Storage and
516       "deploy" in DBIx::Class::Schema.
517
518       The SQL::Translator (not DBI) database driver name can be explicitly
519       provided in $type, otherwise the result of "sqlt_type" is used as
520       default.
521
522       $directory is used to return statements from files in a previously
523       created "create_ddl_dir" directory and is optional. The filenames are
524       constructed from "ddl_filename" in DBIx::Class::Schema, the schema name
525       and the $version.
526
527       If no $directory is specified then the statements are constructed on
528       the fly using SQL::Translator and $version is ignored.
529
530       See "METHODS" in SQL::Translator for a list of values for $sqlt_args.
531
532   datetime_parser
533       Returns the datetime parser class
534
535   datetime_parser_type
536       Defines the datetime parser class - currently defaults to
537       DateTime::Format::MySQL
538
539   build_datetime_parser
540       See "datetime_parser"
541
542   is_replicating
543       A boolean that reports if a particular DBIx::Class::Storage::DBI is set
544       to replicate from a master database.  Default is undef, which is the
545       result returned by databases that don't support replication.
546
547   lag_behind_master
548       Returns a number that represents a certain amount of lag behind a
549       master db when a given storage is replicating.  The number is database
550       dependent, but starts at zero and increases with the amount of lag.
551       Default in undef
552
553   relname_to_table_alias
554       Arguments: $relname, $join_count
555       Return Value: $alias
556
557       DBIx::Class uses DBIx::Class::Relationship names as table aliases in
558       queries.
559
560       This hook is to allow specific DBIx::Class::Storage drivers to change
561       the way these aliases are named.
562
563       The default behavior is ""$relname_$join_count" if $join_count > 1",
564       otherwise "$relname".
565

USAGE NOTES

567   DBIx::Class and AutoCommit
568       DBIx::Class can do some wonderful magic with handling exceptions,
569       disconnections, and transactions when you use "AutoCommit => 1" (the
570       default) combined with txn_do for transaction support.
571
572       If you set "AutoCommit => 0" in your connect info, then you are always
573       in an assumed transaction between commits, and you're telling us you'd
574       like to manage that manually.  A lot of the magic protections offered
575       by this module will go away.  We can't protect you from exceptions due
576       to database disconnects because we don't know anything about how to
577       restart your transactions.  You're on your own for handling all sorts
578       of exceptional cases if you choose the "AutoCommit => 0" path, just as
579       you would be with raw DBI.
580

FURTHER QUESTIONS?

582       Check the list of additional DBIC resources.
583
585       This module is free software copyright by the DBIx::Class (DBIC)
586       authors. You can redistribute it and/or modify it under the same terms
587       as the DBIx::Class library.
588
589
590
591perl v5.32.1                      2021-01-27      DBIx::Class::Storage::DBI(3)
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