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NetSDS::DBI::Table.3pm

NAME

NetSDS::DBI::Table

SYNOPSIS

         use NetSDS::DBI::Table;
 
         my $q = NetSDS::DBI::Table->new(
                 dsn    => 'dbi:Pg:dbname=netsdsdb;host=127.0.0.1',
                 user   => 'netsds',
                 passwd => 'test',
                 table  => 'public.messages',
         ) or warn NetSDS::DBI::Table->errstr();
 
 

DESCRIPTION

"NetSDS::DBI::Table" module provides commonly used CRUD functionality for data stored in single database.

Main idea was that we can agree about some limitations:

* every such table contains "id" field that is primary key

* we use PostgreSQL DBMS with all it's features

CLASS API

new([...]) - class constructor

         my $tbl = NetSDS::DBI::Table->new(
                 dsn => 'dbi:Pg:dbname=content',
                 login => 'netsds',
                 passwd => 'topsecret,
                 table => 'content.meta',
         );
 
 

fetch(%params) - get records from table as array of hashrefs

Paramters (hash):

* fields - fetch fields by list

* filter - arrayref of SQL expressions like "status = 'active'" for "WHERE" clause

* order - arrayref of SQL expressions like "id desc" for "ORDER BY" clause

* limit - max number of records to fetch (LIMIT N)

* offset - records to skip from beginning (OFFSET N)

* for_update - records selected for further update within current transaction

Returns: message as array of hashrefs

Sample:

         my @messages = $q->fetch(
                 fields => ['id', 'now() as time'],
                 filter => ['msg_status = 5', 'date_received < now()'], # where msg_status=5 and date_received < now()
                 order  => ['id desc', 'src_addr'], # order by id desc, src_addr
                 limit => 3, # fetch 3 records
                 offset => 5, # from 6-th record
                 for_update => 1, # for update
         )
 
 

insert_row(%key_val_pairs) - insert record into table

Paramters: record fields as hash

Returns: id of inserted record

         my $user_id = $tbl->insert_row(
                 'login' => 'vasya',
                 'password' => $encrypted_passwd,
         );
 
 

insert(@records_list) - mass insert

Paramters: list of records (as hashrefs)

Returns: array of inserted records ``id''

This method allows mass insert of records.

         my @user_ids = $tbl->insert(
                 { login => 'vasya', password => $str1 },
                 { login => 'masha', password => $str2 },
                 { login => 'petya', password => $str3, active => 'false' },
         );
 
 

Warning! This method use separate INSERT queries and in fact is only wrapper for multiple "insert_row()" calls. So it's not so fast as one insert but allows to use different key-value pairs for different records.

update_row($id, %params) - update record parameters

Paramters: id, new parameters as hash

Returns: updated record as hash

Example:

         my %upd = $table->update_row($msg_id,
                 status => 'failed',
                 dst_addr => '380121234567',
                 );
 
 

After this %upd hash will contain updated table record.

update(%params) - update records by filter

Paramters: filter, new values

         $tbl->update(
                 filter => ['active = true', 'created > '2008-01-01'],
                 set => {
                         info => 'Created after 2007 year',
                 }
         );
 
 

get_count(%params) - retrieve number of records

Just return total number of records by calling:

         # SELECT COUNT(id) FROM schema.table
         my $count = $tbl->get_count();
 
         my $count_active = $tbl->get_count(filter => ['active = true']);
 
 

delete_by_id(@ids) - delete records by identifier

Paramters: list of record id

Returns: 1 if ok, undef if error

Method deletes records from SQL table by it's identifiers.

         if ($tbl->remove(5, 8 ,19)) {
                 print "Records successfully removed.";
         }
 
 

delete(@filters) - delete records

Paramters: list of filters

Returns: 1 if ok, undef if error

         $tbl->delete(
                 'active = false',
                 'expire < now()',
         );
 
 

get_fields() - get list of fields

Example:

         my @fields = @{ $tbl->get_fields() };
         print "Table fields: " . join (', ', @fields);
 
 

has_field($field) - check if field exists

Paramters: field name

Example:

         if ($tbl->has_field('uuid')) {
                 $tbl->call("delete tbldata where uuid=?", $uuid);
         }
 
 

NOTE: this method works only for restricted tables that use "fields" parameter at construction time.

EXAMPLES

See "samples/test_db_table.pl" script

BUGS

Bad documentation

SEE ALSO

NetSDS::DBI

<http://en.wikipedia.org/wiki/Create,_read,_update_and_delete>

TODO

None

AUTHOR

Michael Bochkaryov <misha@rattler.kiev.ua>

LICENSE

Copyright (C) 2008-2009 Net Style Ltd.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA