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DBIx::Class::Storage::DBI(3)         User Contributed Perl Documentation        DBIx::Class::Storage::DBI(3)



NAME
       DBIx::Class::Storage::DBI - DBI storage handler

SYNOPSIS
         my $schema = MySchema->connect('dbi:SQLite:my.db');

         $schema->storage->debug(1);

         my @stuff = $schema->storage->dbh_do(
           sub {
             my ($storage, $dbh, @args) = @_;
             $dbh->do("DROP TABLE authors");
           },
           @column_list
         );

         $schema->resultset('Book')->search({
            written_on => $schema->storage->datetime_parser->format_datetime(DateTime->now)
         });

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

METHODS
   connect_info
       This method is normally called by "connection" in DBIx::Class::Schema, which encapsulates its
       argument list in an arrayref before passing them here.

       The argument list may contain:

       •   The same 4-element argument set one would normally pass to "connect" in DBI, optionally followed
           by extra attributes recognized by DBIx::Class:

             $connect_info_args = [ $dsn, $user, $password, \%dbi_attributes?, \%extra_attributes? ];

       •   A single code reference which returns a connected DBI database handle optionally followed by
           extra attributes recognized by DBIx::Class:

             $connect_info_args = [ sub { DBI->connect (...) }, \%extra_attributes? ];

       •   A single hashref with all the attributes and the dsn/user/password mixed together:

             $connect_info_args = [{
               dsn => $dsn,
               user => $user,
               password => $pass,
               %dbi_attributes,
               %extra_attributes,
             }];

             $connect_info_args = [{
               dbh_maker => sub { DBI->connect (...) },
               %dbi_attributes,
               %extra_attributes,
             }];

           This is particularly useful for Catalyst based applications, allowing the following config
           (Config::General style):

             <Model::DB>
               schema_class   App::DB
               <connect_info>
                 dsn          dbi:mysql:database=test
                 user         testuser
                 password     TestPass
                 AutoCommit   1
               </connect_info>
             </Model::DB>

           The "dsn"/"user"/"password" combination can be substituted by the "dbh_maker" key whose value is
           a coderef that returns a connected DBI database handle

       Please note that the DBI docs recommend that you always explicitly set "AutoCommit" to either _ or 1.
       DBIx::Class further recommends that it be set to 1, and that you perform transactions via our
       "txn_do" in DBIx::Class::Schema method.  DBIx::Class will set it to 1 if you do not do explicitly set
       it to zero.  This is the default for most DBDs. See "DBIx::Class and AutoCommit" for details.

       DBIx::Class specific connection attributes

       In addition to the standard DBI connection attributes, DBIx::Class recognizes the following
       connection options. These options can be mixed in with your other DBI connection attributes, or
       placed in a separate hashref ("\%extra_attributes") as shown above.

       Every time "connect_info" is invoked, any previous settings for these options will be cleared before
       setting the new ones, regardless of whether any options are specified in the new "connect_info".

       on_connect_do
           Specifies things to do immediately after connecting or re-connecting to the database.  Its value
           may contain:

           a scalar
               This contains one SQL statement to execute.

           an array reference
               This contains SQL statements to execute in order.  Each element contains a string or a code
               reference that returns a string.

           a code reference
               This contains some code to execute.  Unlike code references within an array reference, its
               return value is ignored.

       on_disconnect_do
           Takes arguments in the same form as "on_connect_do" and executes them immediately before
           disconnecting from the database.

           Note, this only runs if you explicitly call "disconnect" on the storage object.

       on_connect_call
           A more generalized form of "on_connect_do" that calls the specified "connect_call_METHOD" methods
           in your storage driver.

             on_connect_do => 'select 1'

           is equivalent to:

             on_connect_call => [ [ do_sql => 'select 1' ] ]

           Its values may contain:

           a scalar
               Will call the "connect_call_METHOD" method.

           a code reference
               Will execute "$code->($storage)"

           an array reference
               Each value can be a method name or code reference.

           an array of arrays
               For each array, the first item is taken to be the "connect_call_" method name or code
               reference, and the rest are parameters to it.

           Some predefined storage methods you may use:

           do_sql
               Executes a SQL string or a code reference that returns a SQL string. This is what
               "on_connect_do" and "on_disconnect_do" use.

               It can take:

               a scalar
                   Will execute the scalar as SQL.

               an arrayref
                   Taken to be arguments to "do" in DBI, the SQL string optionally followed by the
                   attributes hashref and bind values.

               a code reference
                   Will execute "$code->($storage)" and execute the return array refs as above.

           datetime_setup
               Execute any statements necessary to initialize the database session to return and accept
               datetime/timestamp values used with DBIx::Class::InflateColumn::DateTime.

               Only necessary for some databases, see your specific storage driver for implementation
               details.

       on_disconnect_call
           Takes arguments in the same form as "on_connect_call" and executes them immediately before
           disconnecting from the database.

           Calls the "disconnect_call_METHOD" methods as opposed to the "connect_call_METHOD" methods called
           by "on_connect_call".

           Note, this only runs if you explicitly call "disconnect" on the storage object.

       disable_sth_caching
           If set to a true value, this option will disable the caching of statement handles via
           "prepare_cached" in DBI.

       limit_dialect
           Sets a specific SQL::Abstract::Limit-style limit dialect, overriding the default
           "sql_limit_dialect" setting of the storage (if any). For a list of available limit dialects see
           DBIx::Class::SQLMaker::LimitDialects.

       quote_names
           When true automatically sets "quote_char" and "name_sep" to the characters appropriate for your
           particular RDBMS. This option is preferred over specifying "quote_char" directly.

       quote_char
           Specifies what characters to use to quote table and column names.

           "quote_char" expects either a single character, in which case is it is placed on either side of
           the table/column name, or an arrayref of length 2 in which case the table/column name is placed
           between the elements.

           For example under MySQL you should use "quote_char => '`'", and for SQL Server you should use
           "quote_char => [qw/[ ]/]".

       name_sep
           This parameter is only useful in conjunction with "quote_char", and is used to specify the
           character that separates elements (schemas, tables, columns) from each other. If unspecified it
           defaults to the most commonly used ".".

       unsafe
           This Storage driver normally installs its own "HandleError", sets "RaiseError" and
           "ShowErrorStatement" on, and sets "PrintError" off on all database handles, including those
           supplied by a coderef.  It does this so that it can have consistent and useful error behavior.

           If you set this option to a true value, Storage will not do its usual modifications to the
           database handle's attributes, and instead relies on the settings in your connect_info DBI options
           (or the values you set in your connection coderef, in the case that you are connecting via
           coderef).

           Note that your custom settings can cause Storage to malfunction, especially if you set a
           "HandleError" handler that suppresses exceptions and/or disable "RaiseError".

       auto_savepoint
           If this option is true, DBIx::Class will use savepoints when nesting transactions, making it
           possible to recover from failure in the inner transaction without having to abort all outer
           transactions.

       cursor_class
           Use this argument to supply a cursor class other than the default
           DBIx::Class::Storage::DBI::Cursor.

       Some real-life examples of arguments to "connect_info" and "connect" in DBIx::Class::Schema

         # Simple SQLite connection
         ->connect_info([ 'dbi:SQLite:./foo.db' ]);

         # Connect via subref
         ->connect_info([ sub { DBI->connect(...) } ]);

         # Connect via subref in hashref
         ->connect_info([{
           dbh_maker => sub { DBI->connect(...) },
           on_connect_do => 'alter session ...',
         }]);

         # A bit more complicated
         ->connect_info(
           [
             'dbi:Pg:dbname=foo',
             'postgres',
             'my_pg_password',
             { AutoCommit => 1 },
             { quote_char => q{"} },
           ]
         );

         # Equivalent to the previous example
         ->connect_info(
           [
             'dbi:Pg:dbname=foo',
             'postgres',
             'my_pg_password',
             { AutoCommit => 1, quote_char => q{"}, name_sep => q{.} },
           ]
         );

         # Same, but with hashref as argument
         # See parse_connect_info for explanation
         ->connect_info(
           [{
             dsn         => 'dbi:Pg:dbname=foo',
             user        => 'postgres',
             password    => 'my_pg_password',
             AutoCommit  => 1,
             quote_char  => q{"},
             name_sep    => q{.},
           }]
         );

         # Subref + DBIx::Class-specific connection options
         ->connect_info(
           [
             sub { DBI->connect(...) },
             {
                 quote_char => q{`},
                 name_sep => q{@},
                 on_connect_do => ['SET search_path TO myschema,otherschema,public'],
                 disable_sth_caching => 1,
             },
           ]
         );

   on_connect_do
       This method is deprecated in favour of setting via "connect_info".

   on_disconnect_do
       This method is deprecated in favour of setting via "connect_info".

   dbh_do
       Arguments: ($subref | $method_name), @extra_coderef_args?

       Execute the given $subref or $method_name using the new exception-based connection management.

       The first two arguments will be the storage object that "dbh_do" was called on and a database handle
       to use.  Any additional arguments will be passed verbatim to the called subref as arguments 2 and
       onwards.

       Using this (instead of $self->_dbh or $self->dbh) ensures correct exception handling and reconnection
       (or failover in future subclasses).

       Your subref should have no side-effects outside of the database, as there is the potential for your
       subref to be partially double-executed if the database connection was stale/dysfunctional.

       Example:

         my @stuff = $schema->storage->dbh_do(
           sub {
             my ($storage, $dbh, @cols) = @_;
             my $cols = join(q{, }, @cols);
             $dbh->selectrow_array("SELECT $cols FROM foo");
           },
           @column_list
         );

   disconnect
       Our "disconnect" method also performs a rollback first if the database is not in "AutoCommit" mode.

   with_deferred_fk_checks
       Arguments: $coderef
       Return Value: The return value of $coderef

       Storage specific method to run the code ref with FK checks deferred or in MySQL's case disabled
       entirely.

   connected
       Arguments: none
       Return Value: 1|0

       Verifies that the current database handle is active and ready to execute an SQL statement (e.g. the
       connection did not get stale, server is still answering, etc.) This method is used internally by
       "dbh".

   dbh
       Returns a $dbh - a data base handle of class DBI. The returned handle is guaranteed to be healthy by
       implicitly calling "connected", and if necessary performing a reconnection before returning. Keep in
       mind that this is very expensive on some database engines. Consider using "dbh_do" instead.

   select
       Arguments: $ident, $select, $condition, $attrs

       Handle a SQL select statement.

   sql_limit_dialect
       This is an accessor for the default SQL limit dialect used by a particular storage driver. Can be
       overridden by supplying an explicit "limit_dialect" to "connect" in DBIx::Class::Schema. For a list
       of available limit dialects see DBIx::Class::SQLMaker::LimitDialects.

   sth
       Arguments: $sql

       Returns a DBI sth (statement handle) for the supplied SQL.

   last_insert_id
       Return the row id of the last insert.

   _native_data_type
       Arguments: $type_name

       This API is EXPERIMENTAL, will almost definitely change in the future, and currently only used by
       ::AutoCast and ::Sybase::ASE.

       The default implementation returns "undef", implement in your Storage driver if you need this
       functionality.

       Should map types from other databases to the native RDBMS type, for example "VARCHAR2" to "VARCHAR".

       Types with modifiers should map to the underlying data type. For example, "INTEGER AUTO_INCREMENT"
       should become "INTEGER".

       Composite types should map to the container type, for example "ENUM(foo,bar,baz)" becomes "ENUM".

   sqlt_type
       Returns the database driver name.

   bind_attribute_by_data_type
       Given a datatype from column info, returns a database specific bind attribute for
       "$dbh->bind_param($val,$attribute)" or nothing if we will let the database planner just handle it.

       Generally only needed for special case column types, like bytea in postgres.

   is_datatype_numeric
       Given a datatype from column_info, returns a boolean value indicating if the current RDBMS considers
       it a numeric value. This controls how "set_column" in DBIx::Class::Row decides whether to mark the
       column as dirty - when the datatype is deemed numeric a "!=" comparison will be performed instead of
       the usual "eq".

   create_ddl_dir
       Arguments: $schema \@databases, $version, $directory, $preversion, \%sqlt_args

       Creates a SQL file based on the Schema, for each of the specified database engines in "\@databases"
       in the given directory.  (note: specify SQL::Translator names, not DBI driver names).

       Given a previous version number, this will also create a file containing the ALTER TABLE statements
       to transform the previous schema into the current one. Note that these statements may contain "DROP
       TABLE" or "DROP COLUMN" statements that can potentially destroy data.

       The file names are created using the "ddl_filename" method below, please override this method in your
       schema if you would like a different file name format. For the ALTER file, the same format is used,
       replacing $version in the name with "$preversion-$version".

       See "METHODS" in SQL::Translator for a list of values for "\%sqlt_args".  The most common value for
       this would be "{ add_drop_table => 1 }" to have the SQL produced include a "DROP TABLE" statement for
       each table created. For quoting purposes supply "quote_table_names" and "quote_field_names".

       If no arguments are passed, then the following default values are assumed:

       databases  - ['MySQL', 'SQLite', 'PostgreSQL']
       version    - $schema->schema_version
       directory  - './'
       preversion - <none>

       By default, "\%sqlt_args" will have

        { add_drop_table => 1, ignore_constraint_names => 1, ignore_index_names => 1 }

       merged with the hash passed in. To disable any of those features, pass in a hashref like the
       following

        { ignore_constraint_names => 0, # ... other options }

       WARNING: You are strongly advised to check all SQL files created, before applying them.

   deployment_statements
       Arguments: $schema, $type, $version, $directory, $sqlt_args

       Returns the statements used by "deploy" and "deploy" in DBIx::Class::Schema.

       The SQL::Translator (not DBI) database driver name can be explicitly provided in $type, otherwise the
       result of "sqlt_type" is used as default.

       $directory is used to return statements from files in a previously created "create_ddl_dir" directory
       and is optional. The filenames are constructed from "ddl_filename" in DBIx::Class::Schema, the schema
       name and the $version.

       If no $directory is specified then the statements are constructed on the fly using SQL::Translator
       and $version is ignored.

       See "METHODS" in SQL::Translator for a list of values for $sqlt_args.

   datetime_parser
       Returns the datetime parser class

   datetime_parser_type
       Defines the datetime parser class - currently defaults to DateTime::Format::MySQL

   build_datetime_parser
       See "datetime_parser"

   is_replicating
       A boolean that reports if a particular DBIx::Class::Storage::DBI is set to replicate from a master
       database.  Default is undef, which is the result returned by databases that don't support
       replication.

   lag_behind_master
       Returns a number that represents a certain amount of lag behind a master db when a given storage is
       replicating.  The number is database dependent, but starts at zero and increases with the amount of
       lag. Default in undef

   relname_to_table_alias
       Arguments: $relname, $join_count

       DBIx::Class uses DBIx::Class::Relationship names as table aliases in queries.

       This hook is to allow specific DBIx::Class::Storage drivers to change the way these aliases are
       named.

       The default behavior is ""$relname_$join_count" if $join_count > 1", otherwise "$relname".

USAGE NOTES
   DBIx::Class and AutoCommit
       DBIx::Class can do some wonderful magic with handling exceptions, disconnections, and transactions
       when you use "AutoCommit => 1" (the default) combined with txn_do for transaction support.

       If you set "AutoCommit => 0" in your connect info, then you are always in an assumed transaction
       between commits, and you're telling us you'd like to manage that manually.  A lot of the magic
       protections offered by this module will go away.  We can't protect you from exceptions due to
       database disconnects because we don't know anything about how to restart your transactions.  You're
       on your own for handling all sorts of exceptional cases if you choose the "AutoCommit => 0" path,
       just as you would be with raw DBI.

AUTHORS
       Matt S. Trout <mst@shadowcatsystems.co.uk>

       Andy Grundman <andy@hybridized.org>

LICENSE
       You may distribute this code under the same terms as Perl itself.



perl v5.12.5                                     2011-07-27                     DBIx::Class::Storage::DBI(3)