Raku TOP Driver - The common driver for Raku TOP backends


NAME

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head

The parent class for all the different Database Drivers (backends).


code

=begin code

role	Database::Driver

=end code


method	useTable(Table :$table, *%params)


Returns a table belonging to the database.  Parameters vary from driver to driver.


	method	useTable(Table :$table, *%params) {...}
	#method	useTable(Table :$table, Str :$action = 'use', :%fields = {}) {
	#method	useTable(Table :$table, *%params) {
	#method	useTable(Table :$table, Str :$filename) {

}



=begin code

role	Table::Driver does Associative does Positional {

=end code



role	Table::Driver does Associative does Positional {
	

defn

	has				%.field-indices;

	has	Str			@!field-names;		# For keeping the fields in order

	

.new(Database::Driver :$database, Relation :$frontend-object, Str :$action, Str :%fields)


	has	Relation			$!frontend-object	is built is required;
	

	has	Database::Driver	$!database			is built;		# Links to the database
	# TODO: Make the above "is required" once the Memory driver supports it

	# Only used during initialisation
	has	Bool		$!init-create = False;
	has	Bool		$!init-alter = False;
	has 			%.init-fields;		# Field definitions to be used during initialisation

	submethod	TWEAK(
			Table :$frontend-object,
			

			:%fields
	) {
		my $name = $frontend-object.name;

		# Existence check, & set InitCreate
		given $action {
			when 'create' {
				self.exists(true-error => "Error: Relation '$name' already exists");
				$!init-create = True;
			}
			when /^(alter|use)$/ {
				self.exists(false-error => "Error: Can't find Relation '$name'");
			}
			when /^(can\-create|ensure)$/ {
				self.exists() or $!init-create = True;
			}
			default {
				die "Error: Unknown action '$action' when calling useTable";
			}
		}

		# Conformance check & set InitAlter
		if ! $!init-create and $action ~~ /^(alter|ensure)$/ {
			my Bool $conforms = self.relation-conforms(%fields);
			$conforms or $!init-alter = True;
		}
	}

	

Returns True if the table already exists.


method	.exists(Str :$true-error, Str :$false-error)


If $true-error is passed, and the table exists, the function will die with the passed error.
	If $false-error is passed, and the table doesn't exist, the function will die with the passed error.


	method	exists(Str :$true-error, Str :$false-error) {
		my Bool $exists =  self.raw-exists();
		$exists and $true-error.defined and die "{$true-error} in database '{$!database.database-name}'";
		! $exists and $false-error.defined and die "{$false-error} in database '{$!database.database-name}'";
		return $exists;
	}
	##### Abstracts
	method fill_from_aoh(@rows) {...}
	method	raw-exists() {...}	# Helper function for .exists, above

	# Associative interface, used for fields
	# 	Must: AT-KEY, EXISTS-KEY
	#	May: DELETE-KEY, ASSIGN-KEY, BIND-KEY, STORE

	# Field (Associative) key locator
	method AT-KEY(\key) is raw {
		Proxy.new(
			FETCH => {
				with %!field-indices.AT-KEY(key) {
					@!fields.AT-POS($_)
				}
				else { Nil }
			},
			STORE => -> $, \value {
				#				say "Storing " ~ join('#', key, value);
				with %!field-indices.AT-KEY(key) {
					@!fields.ASSIGN-POS($_, value)
				}
				else {
					my int $index = @!field-names.elems;
					@!field-names.ASSIGN-POS($index, key);
					%!field-indices.BIND-KEY(key, $index);
					@!fields.ASSIGN-POS($index, value);
				}
			}
		)
	}

	

.add-field(Table :$relation, Str :$name, Any:U $type)


	method	add-field(
		# TODO: Try to replace "relation" with "self"; if that doesn't work, then document
		Table :$relation,
		

		Any:U :$type
	) {
		%!field-indices{$name}:exists and die "Error: Can't create field '$name' because it already exists";
		self.{$name} = Field.new(:$relation, :$name, :$type);
		#@!fields.push(self.{$name});
		#@!field-names.push($name);
	}
}



root

Raku classes to implement the in-memory table store


Raku *::Driver::Memory


The common driver for Raku TOP backends


React

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=begin React :component<HeaderCol> :id<footer>  
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Raku TOP Driver

NAME

AUTHOR

Database::Driver

Methods

.useTable

Table::Driver

Attributes

Methods

.new

exists

.add-field

TOP v0.0.1

Authors

License

Dependencies

Test Dependencies

Provides

Documentation