SQL::Statement::Function(3pm)

Usage

  # this class does not have a common constructor, because all derived classes
  # have their special requirements

  # create an user function term with an SQL::Statement object as owner,
  # specifying the function name, the subroutine name (full qualified)
  # and the parameters to the subroutine
  my $term = SQL::Statement::Function::UserFunc->new( $owner, $name, $sub, \@params );
  # access the result of that operation
  $term->value( $eval );

  # create an user function term with an SQL::Statement object as owner,
  # specifying the expression to evaluate and the parameters to the subroutine
  my $term = SQL::Statement::NumericEval->new( $owner, $expr, \@params );
  # access the result of that operation
  $term->value( $eval );

  # create an trim function term with an SQL::Statement object as owner,
  # specifying the spec, char and the parameters to the subroutine
  my $term = SQL::Statement::Trim->new( $owner, $spec, $char, \@params );
  # access the result of that operation
  $term->value( $eval );

  # create an substr function term with an SQL::Statement object as owner,
  # specifying the start and length of the sub string to extract from the
  # first element of \@params
  my $term = SQL::Statement::SubString->new( $owner, $start, $length, \@params );
  # access the result of that operation
  $term->value( $eval );

  # create an substr function term with an SQL::Statement object as owner
  # and \@params to concatenate
  my $term = SQL::Statement::StrConcat->new( $owner, \@params );
  # access the result of that operation
  $term->value( $eval );

Overview

SQL::Statement::Function is an abstract base class providing the interface for all function executing terms.

Inheritance

  SQL::Statement::Function
  ISA SQL::Statement::Term

Methods

Destroy

Destroys the term and undefines the weak reference to the owner as well as the reference to the parameter list.

Overview

SQL::Statement::Function::UserFunc implements a term which returns the result of the specified subroutine.

Inheritance

  SQL::Statement::Function
  ISA SQL::Statement::Term

Methods

new

Instantiates a new "SQL::Statement::Function::UserFunc" instance.

value

Invokes the given subroutine with the values of the params and return it's result:

    my @params = map { $_->value($eval); } @{ $self->{PARAMS} };
    return $subpkg->$subname( $self->{OWNER}, @params );

Overview

SQL::Statement::Function::NumericEval implements the numeric evaluation of a term. All parameters are expected to be numeric.

Inheritance

  SQL::Statement::Function::NumericEval
  ISA SQL::Statement::Function
    ISA SQL::Statement::Term

Methods

new

Instantiates a new "SQL::Statement::Function::NumericEval" instance. Takes $owner, $expr and \@params as arguments (in specified order).

value

Returns the result of the evaluated expression.

Overview

SQL::Statement::Function::Trim implements string trimming.

Inheritance

  SQL::Statement::Function::Trim
  ISA SQL::Statement::Function
    ISA SQL::Statement::Term

Methods

new

Instantiates a new "SQL::Statement::Function::Trim" instance. Takes $owner, $spec, $char and \@params as arguments (in specified order).

Meaning of the parameters:

$spec

Can be on of 'LEADING', 'TRAILING' 'BOTH'. Trims the leading chars, trailing chars or at both ends, respectively.

Defaults to 'BOTH'.

$char: The character to trim - defaults to ' '

\@params: Expected to be an array with exact 1 element (more are not evaluated).

value

Returns the trimmed value of first parameter argument.

Overview

SQL::Statement::Function::SubString implements a sub-string extraction term.

Inheritance

  SQL::Statement::Function::SubString
  ISA SQL::Statement::Function
    ISA SQL::Statement::Term

Methods

new

Instantiates a new "SQL::Statement::Function::SubString" instance. Takes $owner, $start, $length and \@params as arguments (in specified order).

Meaning of the parameters:

$start: Specifies the start position to extract the sub-string. This is expected to be a SQL::Statement::Term instance. The first character in a string has the position 1.

$length

Specifies the length of the extracted sub-string. This is expected to be a SQL::Statement::Term instance.

If omitted, everything to the end of the string is returned.

\@params: Expected to be an array with exact 1 element (more are not evaluated).

value

Returns the extracted sub-string value from first parameter argument.

Overview

SQL::Statement::Function::StrConcat implements a string concatenation term.

Inheritance

  SQL::Statement::Function::StrConcat
  ISA SQL::Statement::Function
    ISA SQL::Statement::Term

Methods

new

Instantiates a new "SQL::Statement::Function::StrConcat" instance.

value

Returns the concatenated string composed of the parameter values.

Author and copyright

You may distribute this module under the terms of either the GNU General Public License or the Artistic License, as specified in the Perl README file.

Releases

8 releases since Debian 6.0 (Squeeze); the text changed 5 times.

6.0
7
8
9
10
11–13