Public Member Functions
	__construct ($db=null)
	insert_questions_usage_by_activity (question_usage_by_activity $quba)
	insert_question_attempt (question_attempt $qa, $context)
	insert_question_attempt_step (question_attempt_step $step, $questionattemptid, $seq, $context)
	update_question_attempt_step (question_attempt_step $step, $questionattemptid, $seq, $context)
	load_question_attempt_step ($stepid)
	load_question_attempt ($questionattemptid)
	load_questions_usage_by_activity ($qubaid)
	load_questions_usages_latest_steps (qubaid_condition $qubaids, $slots)
	load_questions_usages_question_state_summary (qubaid_condition $qubaids, $slots)
	load_questions_usages_where_question_in_state (qubaid_condition $qubaids, $summarystate, $slot, $questionid=null, $orderby= 'random', $params, $limitfrom=0, $limitnum=null)
	load_average_marks (qubaid_condition $qubaids, $slots=null)
	load_attempts_at_question ($questionid, qubaid_condition $qubaids)
	update_questions_usage_by_activity (question_usage_by_activity $quba)
	update_question_attempt (question_attempt $qa)
	delete_questions_usage_by_activities (qubaid_condition $qubaids)
	delete_steps ($stepids, $context)
	delete_previews ($questionid)
	update_question_attempt_flag ($qubaid, $questionid, $qaid, $slot, $newstate)
	in_summary_state_test ($summarystate, $equal=true, $prefix= 'summarystates')
	set_max_mark_in_attempts (qubaid_condition $qubaids, $slot, $newmaxmark)
	sum_usage_marks_subquery ($qubaid)
	question_attempt_latest_state_view ($alias, qubaid_condition $qubaids)
	questions_in_use (array $questionids, qubaid_condition $qubaids)
Protected Member Functions
	make_step_record (question_attempt_step $step, $questionattemptid, $seq)
	insert_step_data (question_attempt_step $step, $stepid, $context)
	delete_usage_records_for_mysql (qubaid_condition $qubaids)
	delete_attempt_steps_for_mysql ($test, $params)
	delete_response_files ($contextid, $itemidstest, $params)
	full_states_to_summary_state_sql ()
	latest_step_for_qa_subquery ($questionattemptid= 'qa.id')
Protected Attributes
	$db

Detailed Description

This class controls the loading and saving of question engine data to and from the database.

Copyright:: 2009 The Open University http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later

Definition at line 56 of file datalib.php.

Constructor & Destructor Documentation

__construct ( $ db = null )

Parameters:

moodle_database $db a database connectoin. Defaults to global $DB.

Definition at line 66 of file datalib.php.

Member Function Documentation

delete_attempt_steps_for_mysql	(	$	test,
		$	params
	)		`[protected]`

This function is a work-around for poor MySQL performance with DELETE FROM x WHERE id IN (SELECT ...). We have to use a non-standard syntax to get good performance. See MDL-29520.

Parameters:

string	$test	sql fragment.
array	$params	used by $test.

Definition at line 778 of file datalib.php.

delete_previews ( $ questionid )

Delete all the previews for a given question.

Parameters:

int $questionid question id.

Definition at line 833 of file datalib.php.

delete_questions_usage_by_activities ( qubaid_condition $ qubaids )

Delete a question_usage_by_activity and all its associated question_attempts and question_attempt_steps from the database.

Parameters:

qubaid_condition $qubaids identifies which question useages to delete.

Definition at line 713 of file datalib.php.

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delete_response_files	(	$	contextid,
		$	itemidstest,
		$	params
	)		`[protected]`

Delete all the files belonging to the response variables in the gives question attempt steps.

Parameters:

int	$contextid	the context these attempts belong to.
string	$itemidstest	a bit of SQL that can be used in a WHERE itemid $itemidstest clause. Must use named params.
array	$params	any query parameters used in $itemidstest.

Definition at line 821 of file datalib.php.

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delete_steps	(	$	stepids,
		$	context
	)

Delete all the steps for a question attempt.

Parameters:

int	$qaids	question_attempt id.
context	$context	the context that the $quba belongs to.

Definition at line 792 of file datalib.php.

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delete_usage_records_for_mysql ( qubaid_condition $ qubaids ) [protected]

This function is a work-around for poor MySQL performance with DELETE FROM x WHERE id IN (SELECT ...). We have to use a non-standard syntax to get good performance. See MDL-29520.

Parameters:

qubaid_condition $qubaids identifies which question useages to delete.

Definition at line 759 of file datalib.php.

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full_states_to_summary_state_sql ( ) [protected]

Get all the WHEN 'x' THEN 'y' terms needed to convert the question_attempt_steps.state column to a summary state. Use this like CASE qas.state {$this->full_states_to_summary_state_sql()} END AS summarystate,

Parameters:

string SQL fragment.

Definition at line 868 of file datalib.php.

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in_summary_state_test	(	$	summarystate,
		$	equal = `true`,
		$	prefix = `'summarystates'`
	)

Get the SQL needed to test that question_attempt_steps.state is in a state corresponding to $summarystate.

Parameters:

string	$summarystate	one of inprogress, needsgrading, manuallygraded or autograded
bool	$equal	if false, do a NOT IN test. Default true.

Returns:: string SQL fragment.

Definition at line 884 of file datalib.php.

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insert_question_attempt	(	question_attempt $	qa,
		$	context
	)

Store an entire question_attempt in the database, including all the question_attempt_steps that comprise it.

Parameters:

question_attempt	$qa	the question attempt to store.
context	$context	the context of the owning question_usage_by_activity.

Definition at line 100 of file datalib.php.

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insert_question_attempt_step	(	question_attempt_step $	step,
		$	questionattemptid,
		$	seq,
		$	context
	)

Store a question_attempt_step in the database.

Parameters:

question_attempt_step	$step	the step to store.
int	$questionattemptid	the question attept id this step belongs to.
int	$seq	the sequence number of this stop.
context	$context	the context of the owning question_usage_by_activity.

Definition at line 171 of file datalib.php.

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insert_questions_usage_by_activity ( question_usage_by_activity $ quba )

Store an entire question_usage_by_activity in the database, including all the question_attempts that comprise it.

Parameters:

question_usage_by_activity $quba the usage to store.

Definition at line 80 of file datalib.php.

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insert_step_data	(	question_attempt_step $	step,
		$	stepid,
		$	context
	)		`[protected]`

Helper method used by insert_question_attempt_step and update_question_attempt_step

Parameters:

question_attempt_step	$step	the step to store.
int	$stepid	the id of the step.
context	$context	the context of the owning question_usage_by_activity.

Definition at line 150 of file datalib.php.

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latest_step_for_qa_subquery ( $ questionattemptid = 'qa.id' ) [protected]

Definition at line 973 of file datalib.php.

load_attempts_at_question	(	$	questionid,
		qubaid_condition $	qubaids
	)

Load a question_attempt from the database, including all its steps.

Parameters:

int	$questionid	the question to load all the attempts fors.
qubaid_condition	$qubaids	used to restrict which usages are included in the query. See qubaid_condition.

Returns:: array of question_attempts.

Definition at line 613 of file datalib.php.

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load_average_marks	(	qubaid_condition $	qubaids,
		$	slots = `null`
	)

Load a question_usage_by_activity from the database, including all its question_attempts and all their steps.

Parameters:

qubaid_condition	$qubaids	used to restrict which usages are included in the query. See qubaid_condition.
array	$slots	if null, load info for all quesitions, otherwise only load the averages for the specified questions.

Definition at line 564 of file datalib.php.

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load_question_attempt ( $ questionattemptid )

Load a question_attempt from the database, including all its steps.

Parameters:

int	$questionattemptid	the id of the question attempt to load.
	question_attempt	the question attempt that was loaded.

Definition at line 240 of file datalib.php.

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load_question_attempt_step ( $ stepid )

Load a question_attempt_step from the database.

Parameters:

int	$stepid	the id of the step to load.
	question_attempt_step	the step that was loaded.

Definition at line 204 of file datalib.php.

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load_questions_usage_by_activity ( $ qubaid )

Load a question_usage_by_activity from the database, including all its question_attempts and all their steps.

Parameters:

int	$qubaid	the id of the usage to load.
	question_usage_by_activity	the usage that was loaded.

Definition at line 297 of file datalib.php.

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load_questions_usages_latest_steps	(	qubaid_condition $	qubaids,
		$	slots
	)

Load information about the latest state of each question from the database.

Parameters:

qubaid_condition	$qubaids	used to restrict which usages are included in the query. See qubaid_condition.
array	$slots	A list of slots for the questions you want to konw about.

Returns:: array of records. See the SQL in this function to see the fields available.

Definition at line 357 of file datalib.php.

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load_questions_usages_question_state_summary	(	qubaid_condition $	qubaids,
		$	slots
	)

Load summary information about the state of each question in a group of attempts. This is used, for example, by the quiz manual grading report, to show how many attempts at each question need to be graded.

Parameters:

qubaid_condition	$qubaids	used to restrict which usages are included in the query. See qubaid_condition.
array	$slots	A list of slots for the questions you want to konw about.

Returns:: array The array keys are slot,qestionid. The values are objects with fields $slot, $questionid, $inprogress, $name, $needsgrading, $autograded, $manuallygraded and $all.

Definition at line 407 of file datalib.php.

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load_questions_usages_where_question_in_state	(	qubaid_condition $	qubaids,
		$	summarystate,
		$	slot,
		$	questionid = `null`,
		$	orderby = `'random'`,
		$	params,
		$	limitfrom = `0`,
		$	limitnum = `null`
	)

Get a list of usage ids where the question with slot $slot, and optionally also with question id $questionid, is in summary state $summarystate. Also return the total count of such states.

Only a subset of the ids can be returned by using $orderby, $limitfrom and $limitnum. A special value 'random' can be passed as $orderby, in which case $limitfrom is ignored.

Parameters:

qubaid_condition	$qubaids	used to restrict which usages are included in the query. See qubaid_condition.
int	$slot	The slot for the questions you want to konw about.
int	$questionid	(optional) Only return attempts that were of this specific question.
string	$summarystate	the summary state of interest, or 'all'.
string	$orderby	the column to order by.
array	$params	any params required by any of the SQL fragments.
int	$limitfrom	implements paging of the results. Ignored if $orderby = random or $limitnum is null.
int	$limitnum	implements paging of the results. null = all.

Returns:: array with two elements, an array of usage ids, and a count of the total number.

Definition at line 492 of file datalib.php.

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make_step_record	(	question_attempt_step $	step,
		$	questionattemptid,
		$	seq
	)		`[protected]`

Helper method used by insert_question_attempt_step and update_question_attempt_step

Parameters:

question_attempt_step	$step	the step to store.
int	$questionattemptid	the question attept id this step belongs to.
int	$seq	the sequence number of this stop.

Returns:: stdClass data to insert into the database.

Definition at line 133 of file datalib.php.

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question_attempt_latest_state_view	(	$	alias,
		qubaid_condition $	qubaids
	)

Get a subquery that returns the latest step of every qa in some qubas. Currently, this is only used by the quiz reports. See quiz_attempt_report_table::add_latest_state_join().

Parameters:

string	$alias	alias to use for this inline-view.
qubaid_condition	$qubaids	restriction on which question_usages we are interested in. This is important for performance.

Returns:: array with two elements, the SQL fragment and any params requried.

Definition at line 944 of file datalib.php.

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questions_in_use	(	array $	questionids,
		qubaid_condition $	qubaids
	)

Parameters:

array	$questionids	of question ids.
qubaid_condition	$qubaids	ids of the usages to consider.

Returns:: boolean whether any of these questions are being used by any of those usages.

Definition at line 987 of file datalib.php.

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set_max_mark_in_attempts	(	qubaid_condition $	qubaids,
		$	slot,
		$	newmaxmark
	)

Change the maxmark for the question_attempt with number in usage $slot for all the specified question_attempts.

Parameters:

qubaid_condition	$qubaids	Selects which usages are updated.
int	$slot	the number is usage to affect.
number	$newmaxmark	the new max mark to set.

Definition at line 897 of file datalib.php.

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sum_usage_marks_subquery ( $ qubaid )

Return a subquery that computes the sum of the marks for all the questions in a usage. Which useage to compute the sum for is controlled bu the $qubaid parameter.

See quiz_update_all_attempt_sumgrades() for an example of the usage of this method.

Parameters:

string $qubaid SQL fragment that controls which usage is summed. This will normally be the name of a column in the outer query. Not that this SQL fragment must not contain any placeholders.

Returns:: string SQL code for the subquery.

Definition at line 916 of file datalib.php.

update_question_attempt ( question_attempt $ qa )

Update a question_attempts row to refect any changes in a question_attempt (but not any of its steps).

Parameters:

question_attempt $qa the question attempt that has changed.

Definition at line 693 of file datalib.php.

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update_question_attempt_flag	(	$	qubaid,
		$	questionid,
		$	qaid,
		$	slot,
		$	newstate
	)

Update the flagged state of a question in the database.

Parameters:

int	$qubaid	the question usage id.
int	$questionid	the question id.
int	$sessionid	the question_attempt id.
bool	$newstate	the new state of the flag. true = flagged.

Definition at line 853 of file datalib.php.

update_question_attempt_step	(	question_attempt_step $	step,
		$	questionattemptid,
		$	seq,
		$	context
	)

Update a question_attempt_step in the database.

Parameters:

question_attempt_step	$qa	the step to store.
int	$questionattemptid	the question attept id this step belongs to.
int	$seq	the sequence number of this stop.
context	$context	the context of the owning question_usage_by_activity.