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lib/DBIx/Tree/NestedSet/SQLite.pm

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+package DBIx::Tree::NestedSet::SQLite;
+
+use strict;
+use Carp;
+$DBIx::Tree::NestedSet::SQLite::VERSION='0.12';
+
+################################################################################
+sub new{
+    my $class=shift;
+    $class=ref($class)||$class;
+    my %params=@_;
+    my $self={
+	      dbh		=>	$params{dbh},
+	      left_column_name	=>	$params{left_column_name}	|| 'lft',
+	      right_column_name	=>	$params{right_column_name}	|| 'rght',
+	      table_name	=>	$params{table_name}		|| 'nested_set',
+	      id_name		=>	$params{id_name}		|| 'id',
+	      no_alter_table	=>	$params{no_alter_table}		|| undef,
+	      no_locking	=>	$params{no_locking}		|| undef
+	     };
+    bless $self, $class;
+}
+########################################
+
+
+################################################################################
+sub _lock_tables{
+
+    #Transactions are automatically created by SQLite, according to the docs.
+
+#    my $self=shift;
+#    if(! defined $self->{no_locking}){
+#	$self->{dbh}->do(qq|lock tables $self->{table_name} as n1 write, $self->{table_name} as n2 write, $self->{table_name} write|) 
+#    }
+}
+########################################
+
+
+################################################################################
+sub _unlock_tables{
+
+    #Transactions are automatically created by SQLite, according to the docs.
+
+#    my $self=shift;
+#    if(! defined $self->{no_locking}){
+#	$self->{dbh}->do(qq|unlock tables|) 
+#    }
+}
+########################################
+
+
+################################################################################
+sub _alter_table{
+    my($self,$name)=@_;
+    my $table=$self->{table_name};
+    my $left=$self->{left_column_name};
+    my $right=$self->{right_column_name};
+    my $dbh=$self->{dbh};
+
+    my ($base_create)=$dbh->selectrow_array('select sql from sqlite_master where tbl_name = ? and type="table"',undef,($table));
+    $base_create =~ s/^\s?create\s+table\s+$table\s?(.+)/$1/gim;
+    $dbh->do('create temporary table '.$table.'_temp'.$base_create);
+    $dbh->do("insert into ${table}_temp select * from $table");
+    my $recreate=$base_create;
+    $recreate =~ s/(.+)\)$/$1/gim;
+    $recreate .= ", $name text not null)";
+    my $indeces=$dbh->selectcol_arrayref('select sql from sqlite_master where tbl_name=? and type="index"',undef,($table));
+    $dbh->do("drop table $table");
+    $dbh->do("create table $table ".$recreate);
+    foreach (@$indeces) {
+	$dbh->do($_);
+    }
+    $dbh->do("insert into $table select *,'' from ${table}_temp");
+    $dbh->do("drop table ".$table."_temp");
+}
+########################################
+
+
+################################################################################
+sub _create_default_table{
+    my $self=shift;
+    my $dbh=$self->{dbh};
+    my $left=$self->{left_column_name};
+    my $right=$self->{right_column_name};
+    my $table=$self->{table_name};
+    my $id=$self->{id_name};
+    my ($create_table,$index1,$index2)=_create_table_statements($table,$id,$left,$right);
+    $dbh->do($create_table);
+    $dbh->do($index1);
+    $dbh->do($index2);
+}
+########################################
+
+
+################################################################################
+sub _create_table_statements{
+    my ($table,$id,$left,$right)=@_;
+    return(qq|
+	   CREATE TABLE $table (
+				$id integer primary key,
+				$left mediumint(9) NOT NULL,
+				$right mediumint(9) NOT NULL
+			       )
+	   |,
+	   qq|CREATE INDEX $left on $table($left)|,
+	   qq|CREATE INDEX $right on $table($right)|
+	  );
+}
+########################################
+
+
+################################################################################
+sub _get_default_create_table_statement{
+    my $self=shift;
+    my $left=$self->{left_column_name};
+    my $right=$self->{right_column_name};
+    my $table=$self->{table_name};
+    my $id=$self->{id_name};
+    return(join(";\n",_create_table_statements($table,$id,$left,$right))).";\n";
+}
+########################################
+
+1;
+
+=pod
+
+=head1 NAME
+
+DBIx::Tree::NestedSet::SQLite
+
+=head1 SYNOPSIS
+
+A driver class for L<DBIx::Tree::NestedSet> that implements an SQLite interface. There are no publicly available methods in this class.
+
+=head1 WARNING
+
+You should use this class and L<DBIx::Tree::NestedSet> to create your default table:  The way the create table is done in this class is pretty tightly tied to how the "automatic alteration" is done.
+
+=cut
+