NAME

Oracle::Trigger - Perl class for creating Oracle triggers

SYNOPSIS

use Oracle::Trigger;

my %cfg = ('conn_string'=>'usr/pwd@db', 'table_name'=>'my_ora_tab');
my $ot = Oracle::Trigger->new;
# or combine the two together
my $ot = Oracle::Trigger->new(%cfg);
my $sql= $ot->prepare(%cfg); 
$ot->execute();    # actually create the audit table and trigger

# call the methods directly
my $sql = $ot->create_data_trigger($tn,$cns,$dbh,$trg,$aud); 
my $ar  = $ot->create_data_audit($tn,$cns,$dbh,$aud,$drp); 

DESCRIPTION

This class contains methods to create audit tables and triggers for Oracle tables.

new (conn_string=>'usr/pwd@db',table_name=>'my_table')

Input variables:

$cs  - Oracle connection string in usr/pwd@db
$tn  - Oracle table name without schema

Variables used or routines called:

None

How to use:

my $obj = new Oracle::Trigger;      # or
my $obj = Oracle::Trigger->new;     # or
my $cs  = 'usr/pwd@db';
my $tn  = 'my_table'; 
my $obj = Oracle::Trigger->new(cs=>$cs,tn=>$tn); # or
my $obj = Oracle::Trigger->new('cs',$cs, 'tn',$tn); 

Return: new empty or initialized Oracle::Trigger object.

This method constructs a Perl object and capture any parameters if specified. It creates and defaults the following variables:

$self->{conn_string} = "";       # or $self->{cs}
$self->{table_name}  = "";       # or $self->{tn}  

METHODS

The following are the common methods, routines, and functions defined in this class.

Exported Tag: All

The :all tag includes all the methods or sub-rountines defined in this class.

use Oracle::Trigger qw(:all);

It includes the following sub-routines:

prepare($cs, $tn, $tp)

Input variables:

$cs  - Oracle connection string in usr/pwd@db
$tn  - Oracle table name without schema
$tp  - trigger type
       DATA - trigger to audit a table. This is the default.

Variables used or routines called:

Debug::EchoMessage
  echoMSG - display message
{cs} - connection string
{tn} - table name 
{drop_audit}   - whether to drop audit table if it exists
{audit_table}  - audit table name, default to aud${$tn}
{trigger_name} - trigger name, default to trg${$tn}

How to use:

my $ar = $self->prepare('usr/pwd@db','my_tab');

Return: $hr - a hash array ref containing the following keys:

dbh         - the database handler
sql_audit   - SQL statement for creating the audit table
sql_trigger - SQL statement for creating the trigger

This method performs the following tasks:

1) create a database handler
2) check the existance of the table 
3) generate script for creating audit table
4) generate script for creating trigger

And it sets the following internal variable as well:

{dbh} - database handler
{sql_audit} - sql statements to create audit table
{sql_trigger} - sql statement to create trigger

execute($typ)

Input variables:

$typ - action type:
       TRIGGER - create trigger only 
       AUDIT   - create audit table only
       default - null and will create both

Variables used or routines called:

{dbh} - database handler
{sql_audit} - sql statements to create audit table
{sql_trigger} - sql statement to create trigger

How to use:

my $status = $self->execute();
$self->execute();

Return: 0|1: 0 - OK; 1 - failed

This method submits the sql statement to Oracle server to create audit table or trigger or both. The default is to create both. If the audit table exists, it will skip creating the audit table. You either need to manually drop the table or set {drop_audit} to '1' before you run prepare().

create_data_trigger($tn, $cns, $dbh, $trg, $aud)

Input variables:

$tn  - Oracle table name without schema
$cns - a list of column names separated by comma
$dbh - database handler
$trg - trigger name defaults to "TRG${$tn}"
$aud - audit table name defaults to "AUD${$tn}"

Variables used or routines called:

How to use:

my $tn = 'mytab'; 
my $tg = 'mytab_trg';
my $cns = 'id,name';
my $dbh = $self->get_dbh('usr/pwd@db'); 
# No DB connection: $tn,$cns and default trigger name to trg${$tn}:
my $sql = $self->create_data_trigger($tn,$cns); 
# Need DB connection: $tn,$dbh
$sql = $self->create_data_trigger($tn,'',$dbh,$tg);  
# table does not exist, $cns will be used; if table exists, then
# $cns will be checked agaign column names from table
$sql = $self->create_data_trigger($tn,$cns,$dbh);  

Return: $sql - SQL statement to create a DATA trigger.

This method performs the following tasks:

1) check inputs, table name is required
2) check the existance of the table. 
3) compose columns
4) compose SQL code for creating trigger

An empty string will be returned if the inputs do not meet one of the following cases: a) table name and column list are provided; b) table name and database handler are provided so that column names are obtained from the table; c) table name, column list, and database handler are provided, then column names are obtained from the table and compared with the column list are well. None existing columns in the column list will be excluded from trigger.

create_data_audit($tn, cnsp, $dbh, $aud, $drp)

Input variables:

$tn  - source table name without schema
$cns - column names separated by comma
$dbh - database handler
$aud - audit table name
$drp - whether to drop audit table before creating it
       default is 0 (no)

Variables used or routines called:

How to use:

my $tn  = 'mytab'; 
my $aud = 'aud$mytab';
my $dbh = $self->get_dbh('usr/pwd@db');
# create audit table 
# and default audit name is aud${$tn}:
my $ar = $self->create_data_audit($tn,$cns); 

# give a trigger name
$sql = $self->create_data_audit($tn,$tg);  
# table does not exist, but colun names are provided:
$sql = $self->create_data_audit($tn,'','id,name');  
# if $dbh is provided, the table existence will be checked
$sql = $self->create_data_audit($tn,'','',$dbh);

Return: $ar - array ref containing SQL statements for dropping and creating audit table.

This method performs the following tasks:

1) check inputs, table name is required
2) check the existance of the table. 
3) compose columns
4) compose SQL code for creating trigger

An empty string will be returned if the inputs do not meet one of the following cases: a) table name and column list are provided; b) table name and database handler are provided so that column names are obtained from the table; c) table name, column list, and database handler are provided, then column names are obtained from the table and compared with the column list are well. None existing columns in the column list will be excluded from trigger.

HISTORY

• Version 0.1

  This version is to test the procedures and create DATA trigger.

  04/22/2005 (htu) - finished creating DATA trigger rountines.

• Version 0.2

  04/29/2005 (htu) - modified some descriptions and moved the common routines to Oracle::DML::Common.

• Version 0.21

  Since get_table_definition is moved to Oracle::Schema, we change it here to use Oracle::Schema.

• Version 0.22

  Re-wrote prepare method so that it can prepare SQL statments based on trigger type.

  Added create_data_trigger and create_data_audit methods.

SEE ALSO (some of docs that I check often)

Data::Describe, Oracle::Loader, CGI::Getopt, File::Xcopy, perltoot(1), perlobj(1), perlbot(1), perlsub(1), perldata(1), perlsub(1), perlmod(1), perlmodlib(1), perlref(1), perlreftut(1).

AUTHOR

Copyright (c) 2005 Hanming Tu. All rights reserved.

This package is free software and is provided "as is" without express or implied warranty. It may be used, redistributed and/or modified under the terms of the Perl Artistic License (see http://www.perl.com/perl/misc/Artistic.html)

cpanm Oracle::Trigger

perl -MCPAN -e shell
install Oracle::Trigger