Alzabo
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lib/Alzabo/Runtime/Table.pm view on Meta::CPAN
{
my $self = shift;
my %p = @_;
my $sql = $self->_make_sql(%p);
Alzabo::Runtime::process_where_clause( $sql, $p{where} ) if exists $p{where};
Alzabo::Runtime::process_order_by_clause( $sql, $p{order_by} ) if exists $p{order_by};
if ( exists $p{limit} )
{
$sql->limit( ref $p{limit} ? @{ $p{limit} } : $p{limit} );
}
$sql->debug(\*STDERR) if Alzabo::Debug::SQL;
print STDERR Devel::StackTrace->new if Alzabo::Debug::TRACE;
my @return = $self->schema->driver->one_row( sql => $sql->sql,
bind => $sql->bind )
or return;
my @pk = $self->primary_key;
my (%pk, %prefetch);
@pk{ map { $_->name } @pk } = splice @return, 0, scalar @pk;
# Must be some prefetch pieces
if (@return)
{
@prefetch{ $self->prefetch } = @return;
}
return $self->row_by_pk( pk => \%pk,
prefetch => \%prefetch,
);
}
sub all_rows
{
my $self = shift;
my $sql = $self->_make_sql;
$sql->debug(\*STDERR) if Alzabo::Debug::SQL;
print STDERR Devel::StackTrace->new if Alzabo::Debug::TRACE;
return $self->_cursor_by_sql( @_, sql => $sql );
}
sub _make_sql
{
my $self = shift;
my %p = @_;
logic_exception "Can't make rows for tables without a primary key"
unless $self->primary_key;
my $sql = ( Alzabo::Runtime::sqlmaker( $self->schema, \%p )->
select( $self->primary_key,
$self->prefetch ? $self->columns( $self->prefetch ) : () )->
from( $self ) );
return $sql;
}
sub _cursor_by_sql
{
my $self = shift;
my %p = @_;
validate( @_, { sql => { isa => 'Alzabo::SQLMaker' },
order_by => { type => ARRAYREF | HASHREF | OBJECT,
optional => 1 },
limit => { type => SCALAR | ARRAYREF,
optional => 1 },
( map { $_ => { optional => 1 } } keys %p ) } );
Alzabo::Runtime::process_order_by_clause( $p{sql}, $p{order_by} ) if exists $p{order_by};
if ( exists $p{limit} )
{
$p{sql}->limit( ref $p{limit} ? @{ $p{limit} } : $p{limit} );
}
my $statement = $self->schema->driver->statement( sql => $p{sql}->sql,
bind => $p{sql}->bind,
limit => $p{sql}->get_limit );
return Alzabo::Runtime::RowCursor->new( statement => $statement,
table => $self,
);
}
sub potential_row
{
my $self = shift;
my %p = @_;
logic_exception "Can't make rows for tables without a primary key"
unless $self->primary_key;
my $class = $p{row_class} ? delete $p{row_class} : $self->_row_class;
return $class->new( %p,
state => 'Alzabo::Runtime::RowState::Potential',
table => $self,
);
}
sub row_count
{
my $self = shift;
my %p = @_;
my $count = Alzabo::Runtime::sqlmaker( $self->schema, \%p )->COUNT('*');
return $self->function( select => $count, %p );
}
sub function
{
my $self = shift;
my %p = @_;
my $sql = $self->_select_sql(%p);
my $method =
Alzabo::Utils::is_arrayref( $p{select} ) && @{ $p{select} } > 1 ? 'rows' : 'column';
$sql->debug(\*STDERR) if Alzabo::Debug::SQL;
print STDERR Devel::StackTrace->new if Alzabo::Debug::TRACE;
return $self->schema->driver->$method( sql => $sql->sql,
bind => $sql->bind );
}
sub select
{
my $self = shift;
my $sql = $self->_select_sql(@_);
$sql->debug(\*STDERR) if Alzabo::Debug::SQL;
print STDERR Devel::StackTrace->new if Alzabo::Debug::TRACE;
return $self->schema->driver->statement( sql => $sql->sql,
bind => $sql->bind );
}
use constant
_SELECT_SQL_SPEC => { select => { type => SCALAR | ARRAYREF | OBJECT },
where => { type => ARRAYREF | OBJECT,
optional => 1 },
order_by => { type => ARRAYREF | HASHREF | OBJECT,
optional => 1 },
group_by => { type => ARRAYREF | HASHREF | OBJECT,
optional => 1 },
having => { type => ARRAYREF,
optional => 1 },
limit => { type => SCALAR | ARRAYREF,
optional => 1 },
quote_identifiers => { type => BOOLEAN,
optional => 1 },
};
sub _select_sql
{
my $self = shift;
my %p = validate( @_, _SELECT_SQL_SPEC );
my @funcs = Alzabo::Utils::is_arrayref( $p{select} ) ? @{ $p{select} } : $p{select};
my $sql = Alzabo::Runtime::sqlmaker( $self->schema, \%p )->select(@funcs)->from($self);
Alzabo::Runtime::process_where_clause( $sql, $p{where} )
if exists $p{where};
Alzabo::Runtime::process_group_by_clause( $sql, $p{group_by} )
if exists $p{group_by};
Alzabo::Runtime::process_having_clause( $sql, $p{having} )
if exists $p{having};
Alzabo::Runtime::process_order_by_clause( $sql, $p{order_by} )
if exists $p{order_by};
$sql->limit( ref $p{limit} ? @{ $p{limit} } : $p{limit} ) if $p{limit};
return $sql;
}
sub set_prefetch
{
my $self = shift;
$self->{prefetch} = $self->_canonize_prefetch(@_);
}
sub _canonize_prefetch
{
my $self = shift;
validate_pos( @_, ( { isa => 'Alzabo::Column' } ) x @_ );
foreach my $c (@_)
{
params_exception "Column " . $c->name . " doesn't exist in $self->{name}"
unless $self->has_column( $c->name );
}
return [ map { $_->name } grep { ! $_->is_primary_key } @_ ];
}
sub prefetch
{
my $self = shift;
return ref $self->{prefetch} ? @{ $self->{prefetch} } : ();
}
sub add_group
{
my $self = shift;
validate_pos( @_, ( { isa => 'Alzabo::Column' } ) x @_ );
my @names = map { $_->name } @_;
foreach my $col (@_)
{
params_exception "Column " . $col->name . " doesn't exist in $self->{name}"
unless $self->has_column( $col->name );
next if $col->is_primary_key;
lib/Alzabo/Runtime/Table.pm view on Meta::CPAN
$value or Alzabo::Column object ],
...
]
If the comparison is "BETWEEN", then it should be followed by two
values. If it is "IN" or "NOT IN", then it should be followed by a
list of one or more values.
By default, each clause represented by an array reference is joined
together with an 'AND'. However, you can put the string 'or' between
two array references to cause them to be joined with an 'OR', such as:
[ [ $foo_col, '=', 5 ],
'or',
[ $foo_col, '>', 10 ] ]
which would generate SQL something like:
WHERE foo = 5 OR foo > 10
If you want to be explicit, you can also use the string 'and'.
If you need to group conditionals you can use '(' and ')' strings in
between array references representing a conditional. For example:
[ [ $foo_col, '=', 5 ],
'(',
[ $foo_col, '>', 10 ]
'or',
[ $bar_col, '<', 50, ')' ],
')' ]
which would generate SQL something like:
WHERE foo = 5 AND ( foo > 10 OR bar < 50 )
Make sure that your parentheses balance out or an exception will be
thrown.
You can also use the SQL functions (L<Using SQL
functions|Alzabo::Intro/Using SQL functions>) exported from the
SQLMaker subclass you are using. For example:
[ LENGTH($foo_col), '<', 10 ]
would generate something like:
WHERE LENGTH(foo) < 10
=item * order_by => see below
This parameter can take one of two different values. The simplest
form is to just give it a single column object or SQL function.
Alternatively, you can give it an array reference to a list of column
objects, SQL functions and strings like this:
order_by => [ $col1, COUNT('*'), $col2, 'DESC', $col3, 'ASC' ]
It is important to note that you cannot simply use any arbitrary SQL
function as part of your order by clause. You need to use a function
that is exactly the same as one that was given as part of the "select"
parameter.
=item * group_by => see below
This parameter can take either a single column object or an array of
column objects.
=item * having => same as "where"
This parameter is specified in the same way as the "where" parameter.
=item * limit => $limit or [ $limit, $offset ]
For databases that support LIMIT clauses, this incorporates such a
clause into the SQL.
For databases that don't, the limit will be implemented
programatically as rows are being requested. If an offset is given,
this will be the number of rows skipped in the result set before the
first one is returned.
=back
=head2 Methods that return an C<Alzabo::Runtime::RowCursor> object
The C<rows_where()> and C<all_rows()> methods both return an
L<C<Alzabo::Runtime::RowCursor>|Alzabo::Runtime::RowCursor> object
representing the results of the query. This is the case even for
queries that end up returning one or zero rows, because Alzabo cannot
know in advance how many rows these queries will return.
=head2 rows_where
This method provides a simple way to retrieve a row cursor based on
one or more colum values.
It takes the following parameters, all of which were described in the
L<Common Parameters|Alzabo::Runtime::Table/Common Parameters> section.
=over 4
=item * where
=item * order_by
=item * limit
=back
It returns n
L<C<Alzabo::Runtime::RowCursor>|Alzabo::Runtime::RowCursor> object
representing the query.
Throws: L<C<Alzabo::Exception::Logic>|Alzabo::Exceptions>,
L<C<Alzabo::Exception::Params>|Alzabo::Exceptions>
=head2 all_rows
This method simply returns all the rows in the table.
lib/Alzabo/Runtime/Table.pm view on Meta::CPAN
Throws: L<C<Alzabo::Exception::Logic>|Alzabo::Exceptions>,
L<C<Alzabo::Exception::Params>|Alzabo::Exceptions>
=head2 one_row
This method takes the exact same parameters as the
L<C<rows_where()>|Alzabo::Runtime::table/rows_where> method but
instead of returning a cursor, it returns a single row. This row
represents the first row returned by the database.
Throws: L<C<Alzabo::Exception::Logic>|Alzabo::Exceptions>,
L<C<Alzabo::Exception::Params>|Alzabo::Exceptions>
=head2 potential_row
This method is used to create a new
L<C<Alzabo::Runtime::Row>|Alzabo::Runtime::Row> object, in the
"potential" state.
It takes the following parameters.
=over 4
=item * values => \%values
This should be a hash reference containing column names, just as is
given to L<insert()|/insert>.
It is ok to omit columns that are normally not nullable, but they
cannot be B<explicitly> set to null.
Any values given will be set in the new potential row object. If a
column has a default, and a value for that column is not given, then
the default will be used.
Unlike the L<insert()\/insert> method, you cannot use SQL functions as
values here.
=back
Throws: L<C<Alzabo::Exception::Logic>|Alzabo::Exceptions>,
L<C<Alzabo::Exception::Params>|Alzabo::Exceptions>
=head2 Other Methods
This method returns a count of the rows in the table. It takes the
following parameters:
=head2 row_count
=over 4
=item * where
=back
Throws: L<C<Alzabo::Exception::Logic>|Alzabo::Exceptions>,
L<C<Alzabo::Exception::Params>|Alzabo::Exceptions>
=head2 function and select
These two methods differ only in their return values.
They both take the following parameters:
=over 4
=item * select => $function or [ scalars, SQL functions and/or C<Alzabo::Column> objects ]
If you pass an array reference for this parameter, it may contain
scalars, SQL functions, or column objects. For example:
$table->function( select =>
[ 1,
$foo->column('name'),
LENGTH( $foo->column('name') ) ] );
This is equivalent to the following SQL:
SELECT 1, foo.name, LENGTH( foo.name )
FROM foo
=item * where
=item * order_by
=item * group_by
=item * limit
=back
This method is used to call arbitrary SQL functions such as 'AVG' or
'MAX', or to select arbitrary column data. The function (or
functions) should be the return values from the functions exported by
the SQLMaker subclass that you are using. Please see L<Using SQL
functions|Alzabo/Using SQL functions> for more details.
Throws: L<C<Alzabo::Exception::Logic>|Alzabo::Exceptions>,
L<C<Alzabo::Exception::Params>|Alzabo::Exceptions>
=head3 function() return values
The return value of this method is highly context sensitive.
If you only requested a single element in your "select" parameter,
such as "DISTINCT(foo)", then it returns the first value in scalar
context and all the values as an array in list context.
If you requested multiple functions such as "AVG(foo), MAX(foo)", then
it returns a single array reference, the first row of values, in
scalar context and a list of array references in list context.
=head3 select() return values
This method always returns a new
L<C<Alzabo::DriverStatement>|Alzabo::Driver/Alzabo::DriverStatement>
object containing the results of the query. This object has an
interface very similar to the Alzabo cursor interface, and has methods
such as C<next()>, C<next_as_hash()>, etc.
=head2 alias
This returns an object which can be used in joins to allow a
particular table to be involved in the join under multiple aliases.
This allows for self-joins as well as more complex joins involving
multiple aliases to a given table.
The object returned by this method is more or less identical to a
table object in terms of the methods it supports. This includes
methods that were generated by C<Alzabo::MethodMaker>.
However, B<this object should not be used outside the context of a
join query> because the results will be unpredictable. In addition,
B<the column objects that the aliased table object returns should also
not be used outside of the context of a join>.
=for pod_merge schema
=for pod_merge name
=for pod_merge column
=for pod_merge columns
=for pod_merge has_column
=for pod_merge primary_key
=for pod_merge primary_key_size
=for pod_merge column_is_primary_key
=for pod_merge foreign_keys
=for pod_merge foreign_keys_by_table
=for pod_merge foreign_keys_by_column
=for pod_merge all_foreign_keys
=for pod_merge index
=for pod_merge has_index
=for pod_merge indexes
=for pod_merge attributes
=for pod_merge has_attribute
=for pod_merge comment
=head1 LAZY COLUMN LOADING
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