NAME

SQL::Schema::Trigger - A database trigger

SYNOPSIS

  my $trigger = SQL::Schema::Trigger->new(%attr);

  my $sql = $trigger->create_statement;
  print $sql;

  print "$trigger";

DESCRIPTION

SQL::Schema::Trigger is a class for objects representing a database trigger. The methods of an instanciated object do allow to access the information within a database's data dictionary and to represent them as SQL create statements and the like using the proper SQL dialect.

Constructors

  $trigger = SQL::Schema::Trigger->new(%attr);

The new method instanciates a trigger object. The object is an in memory representation of a (possible) database trigger. The attributes are given as key value pairs by the hash %attr. Possible keys are:

  key               required?   value description

  trigger_name      yes         the name of the trigger (without a
                                preceeding schema name)

  description       yes         the "head" of the trigger's create statement
                                excluding `create trigger ' resp.
                                `create or replace trigger ' but including
                                everything from the trigger's name on up to
                                (but not including) the when_clause

  when_clause       no          the when clause of the trigger everything
                                from `when' until the start of the
                                PL/SQL block (remember: the PL/SQL block
                                starts with `declare' or `begin')

  trigger_body      yes         the PL/SQL block of the trigger including
                                `declare', `begin' and `end;'

All the keys correspond to the columns with the same name from Oracle's data dictionary view user_triggers.

  $trigger = SQL::Schema::Trigger->select($dbh,$name);

The select method fetches the attributes required by new from the database and returns the trigger object. (It calls new internally.)

If the trigger with the name $name could not be found within the database, the method returns undef.

The method's arguments are as follows:

$dbh: A database handle as defined by DBI(3).
$name: The name of the trigger without preceeding schema name.

Methods

The following attribute methods do return the current value of the attributes (as handed over to the new method):

  $name = $trigger->name;
  $description = $trigger->description;
  $when_clause = $trigger->when_clause;
  $trigger_body = $trigger->trigger_body;

  $sql = $trigger->create_statement;
  $sql = "$trigger";

Returns a string containing an SQL statements for creation of this trigger. This method is overloaded with the string operator. So the two examples above are equivalent.

  $sql = $trigger->drop_statement;

Returns a string containing an SQL statement that would drop this trigger.

AUTHOR AND COPYRIGHT

  SQL::Schema::Trigger is Copyright (C) 2000,
    Torsten Hentschel
    Windmuehlenweg 47
    44141 Dortmund
    Germany

    Email: todd@bayleys.ping.de

  All rights reserved.