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DBIx::ContextualFetch.3pm

NAME

DBIx::ContextualFetch - Add contextual fetches to DBI

SYNOPSIS

         my $dbh = DBI->connect(...., { RootClass => "DBIx::ContextualFetch" });
 
         # Modified statement handle methods.
         my $rv = $sth->execute;
         my $rv = $sth->execute(@bind_values);
         my $rv = $sth->execute(\@bind_values, \@bind_cols);
 
         # In addition to the normal DBI sth methods...
         my $row_ref = $sth->fetch;
         my @row     = $sth->fetch;
 
         my $row_ref = $sth->fetch_hash;
         my %row     = $sth->fetch_hash;
 
         my $rows_ref = $sth->fetchall;
         my @rows     = $sth->fetchall;
 
         my $rows_ref = $sth->fetchall_hash;
         my @tbl      = $sth->fetchall_hash;
 
 

DESCRIPTION

It always struck me odd that DBI didn't take much advantage of Perl's context sensitivity. DBIx::ContextualFetch redefines some of the various fetch methods to fix this oversight. It also adds a few new methods for convenience (though not necessarily efficiency).

SET-UP

         my $dbh = DBIx::ContextualFetch->connect(@info);
         my $dbh = DBI->connect(@info, { RootClass => "DBIx::ContextualFetch" });
 
 

To use this method, you can either make sure that everywhere you normall call DBI->connect() you either call it on DBIx::ContextualFetch, or that you pass this as your RootClass. After this DBI will Do The Right Thing and pass all its calls through us.

EXTENSIONS

execute

         $rv = $sth->execute;
         $rv = $sth->execute(@bind_values);
         $rv = $sth->execute(\@bind_values, \@bind_cols);
 
 

execute() is enhanced slightly:

If called with no arguments, or with a simple list, execute() operates normally. When when called with two array references, it performs the functions of bind_param, execute and bind_columns similar to the following:

         $sth->execute(@bind_values);
         $sth->bind_columns(undef, @bind_cols);
 
 

In addition, execute will accept tainted @bind_values. I can't think of what a malicious user could do with a tainted bind value (in the general case. Your application may vary.)

Thus a typical idiom would be:

         $sth->execute([$this, $that], [\($foo, $bar)]);
 
 

Of course, this method provides no way of passing bind attributes through to bind_param or bind_columns. If that is necessary, then you must perform the bind_param, execute, bind_col sequence yourself.

fetch

         $row_ref = $sth->fetch;
         @row     = $sth->fetch;
 
 

A context sensitive version of fetch(). When in scalar context, it will act as fetchrow_arrayref. In list context it will use fetchrow_array.

fetch_hash

         $row_ref = $sth->fetch_hash;
         %row     = $sth->fetch_hash;
 
 

A modification on fetchrow_hashref. When in scalar context, it acts just as fetchrow_hashref() does. In list context it returns the complete hash.

fetchall

         $rows_ref = $sth->fetchall;
         @rows     = $sth->fetchall;
 
 

A modification on fetchall_arrayref. In scalar context it acts as fetchall_arrayref. In list it returns an array of references to rows fetched.

fetchall_hash

         $rows_ref = $sth->fetchall_hash;
         @rows     = $sth->fetchall_hash;
 
 

A mating of fetchall_arrayref() with fetchrow_hashref(). It gets all rows from the hash, each as hash references. In scalar context it returns a reference to an array of hash references. In list context it returns a list of hash references.

ORIGINAL AUTHOR

Michael G Schwern as part of Ima::DBI

CURRENT MAINTAINER

Tony Bowden <tony@tmtm.com>

LICENSE

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

SEE ALSO

DBI. Ima::DBI. Class::DBI.