qubaid_join Class Reference

This class represents a restriction on the set of question_usage ids to include in a larger database query based on JOINing to some other tables. More...

Inheritance diagram for qubaid_join:

Public Member Functions
	__construct ($from, $usageidcolumn, $where='', $params=array())
	Constructor. More...
	from_question_attempts ($alias)
	Get the SQL fragment to go in a FROM clause. More...
	from_where_params ()
	get_hash_code ()
	usage_id_in ()
	usage_id_in_params ()
	where ()

Public Attributes
	$from
	$params
	$usageidcolumn
	$where

Detailed Description

This class represents a restriction on the set of question_usage ids to include in a larger database query based on JOINing to some other tables.

The general form of the query is something like

SELECT qa.id, qa.maxmark FROM $from JOIN {question_attempts} qa ON qa.questionusageid = $usageidcolumn WHERE $where AND qa.slot = 1

where $from, $usageidcolumn and $where are the arguments to the constructor.

Copyright

2010 The Open University

License

http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

Constructor & Destructor Documentation

__construct()

qubaid_join::__construct	(		$from,
			$usageidcolumn,
			$where = '',
			$params = array()
	)

Constructor.

The meaning of the arguments is explained in the class comment.

Parameters

string	$from	SQL fragemnt to go in the FROM clause.
string	$usageidcolumn	the column in $from that should be made equal to the usageid column in the JOIN clause.
string	$where	SQL fragment to go in the where clause.
array	$params	required by the SQL. You must use named parameters.

Reimplemented in qubaids_for_quiz_user, and mod_quiz\question\qubaids_for_users_attempts.

Member Function Documentation

from_question_attempts()

qubaid_join::from_question_attempts

(

$alias

)

Get the SQL fragment to go in a FROM clause.

The SQL that needs to go in the FROM clause when trying to select records from the 'question_attempts' table based on this qubaid_condition.

Parameters

string

$alias

Return values

string

SQL fragment.

Reimplemented from qubaid_condition.

from_where_params()

qubaid_join::from_where_params

(

)

Return values

array

the params needed by a query that uses from_question_attempts() and where().

Reimplemented from qubaid_condition.

get_hash_code()

qubaid_condition::get_hash_code ( )

inherited

Return values

string

40-character hash code that uniquely identifies the combination of properties and class name of this qubaid condition.

usage_id_in()

qubaid_join::usage_id_in

(

)

Return values

string

SQL that can use used in a WHERE qubaid IN (...) query. This method returns the "IN (...)" part.

Reimplemented from qubaid_condition.

usage_id_in_params()

qubaid_join::usage_id_in_params

(

)

Return values

array

the params needed by a query that uses usage_id_in().

Reimplemented from qubaid_condition.

where()

qubaid_join::where

(

)

Return values

string

the SQL that needs to go in the where clause.

Reimplemented from qubaid_condition.

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The documentation for this class was generated from the following file:

• question/engine/datalib.php