Contains database functions split-off from moodlelib, just so you can see

[moodle.git] / lib / database.php

<?PHP // $Id$

/// FUNCTIONS FOR DATABASE HANDLING  ////////////////////////////////

function execute_sql($command, $feedback=true) {
/// Completely general function - it just runs some SQL and reports success.

    global $db;
    
    $result = $db->Execute("$command");

    if ($result) {
        if ($feedback) {
            echo "<P><FONT COLOR=green><B>".get_string("success")."</B></FONT></P>";
        }
        return true;
    } else {
        if ($feedback) {
            echo "<P><FONT COLOR=red><B>".get_string("error")."</B></FONT></P>";
        }
        return false;
    }
}

function modify_database($sqlfile) {
/// Assumes that the input text file consists of a number 
/// of SQL statements ENDING WITH SEMICOLONS.  The semicolons
/// MUST be the last character in a line.
/// Lines that are blank or that start with "#" are ignored.
/// Only tested with mysql dump files (mysqldump -p -d moodle)

    global $CFG;

    if (file_exists($sqlfile)) {
        $success = true;
        $lines = file($sqlfile);
        $command = "";

        while ( list($i, $line) = each($lines) ) {
            $line = chop($line);
            $length = strlen($line);

            if ($length  &&  substr($line, 0, 1) <> "#") { 
                if (substr($line, $length-1, 1) == ";") {
                    $line = substr($line, 0, $length-1);   // strip ;
                    $command .= $line;
                    $command = str_replace("prefix_", $CFG->prefix, $command); // Table prefixes
                    if (! execute_sql($command)) {
                        $success = false;
                    }
                    $command = "";
                } else {
                    $command .= $line;
                }
            }
        }

    } else {
        $success = false;
        echo "<P>Tried to modify database, but \"$sqlfile\" doesn't exist!</P>";
    }

    return $success;
}


function record_exists($table, $field="", $value="", $field2="", $value2="", $field3="", $value3="") {
/// Returns true or false depending on whether the specified record exists

    global $CFG;

    if ($field and $value) {
        $select = "WHERE $field = '$value'";
        if ($field2 and $value2) {
            $select .= " AND $field2 = '$value2'";
            if ($field3 and $value3) {
                $select .= " AND $field3 = '$value3'";
            }
        }
    }

    return record_exists_sql("SELECT * FROM $CFG->prefix$table $select LIMIT 1");
}


function record_exists_sql($sql) {
/// Returns true or false depending on whether the specified record exists
/// The sql statement is provided as a string.

    global $db;

    $rs = $db->Execute($sql);
    if (!$rs) return false;

    if ( $rs->RecordCount() ) {
        return true;
    } else {
        return false;
    }
}


function count_records($table, $field="", $value="", $field2="", $value2="", $field3="", $value3="") {
/// Get all the records and count them

    global $CFG;

    if ($field and $value) {
        $select = "WHERE $field = '$value'";
        if ($field2 and $value2) {
            $select .= " AND $field2 = '$value2'";
            if ($field3 and $value3) {
                $select .= " AND $field3 = '$value3'";
            }
        }
    }

    return count_records_sql("SELECT COUNT(*) FROM $CFG->prefix$table $select");
}

function count_records_sql($sql) {
/// Get all the records and count them
/// The sql statement is provided as a string.

    global $db;

    $rs = $db->Execute("$sql");
    if (!$rs) return 0;

    return $rs->fields[0];
}

function get_record($table, $field, $value, $field2="", $value2="", $field3="", $value3="") {
/// Get a single record as an object

    global $CFG;

    $select = "WHERE $field = '$value'";

    if ($field2 and $value2) {
        $select .= " AND $field2 = '$value2'";
        if ($field3 and $value3) {
            $select .= " AND $field3 = '$value3'";
        }
    }

    return get_record_sql("SELECT * FROM $CFG->prefix$table $select");
}

function get_record_sql($sql) {
/// Get a single record as an object
/// The sql statement is provided as a string.

    global $db;

    $rs = $db->Execute("$sql");
    if (!$rs) return false;

    if ( $rs->RecordCount() == 1 ) {
        return (object)$rs->fields;
    } else {
        return false;
    }
}

function get_records($table, $field="", $value="", $sort="", $fields="*") {
/// Get a number of records as an array of objects
/// Can optionally be sorted eg "time ASC" or "time DESC"
/// If "fields" is specified, only those fields are returned
/// The "key" is the first column returned, eg usually "id"

    global $CFG;

    if ($field and $value) {
        $select = "WHERE $field = '$value'";
    }
    if ($sort) {
        $sortorder = "ORDER BY $sort";
    }

    return get_records_sql("SELECT $fields FROM $CFG->prefix$table $select $sortorder");
}


function get_records_list($table, $field="", $values="", $sort="", $fields="*") {
// Get a number of records as an array of objects
// Differs from get_records() in that the values variable 
// can be a comma-separated list of values eg  "4,5,6,10"
// Can optionally be sorted eg "time ASC" or "time DESC"
// The "key" is the first column returned, eg usually "id"

    global $CFG;

    if ($field and $value) {
        $select = "WHERE $field in ($values)";
    }
    if ($sort) {
        $sortorder = "ORDER BY $sort";
    }

    return get_records_sql("SELECT $fields FROM $CFG->prefix$table $select $sortorder");
}


function get_records_sql($sql) {
// Get a number of records as an array of objects
// The "key" is the first column returned, eg usually "id"
// The sql statement is provided as a string.

    global $db;

    $rs = $db->Execute("$sql");
    if (!$rs) return false;

    if ( $rs->RecordCount() > 0 ) {
        if ($records = $rs->GetAssoc(true)) {
            foreach ($records as $key => $record) {
                $objects[$key] = (object) $record;
            }
            return $objects;
        } else {
            return false;
        }
    } else {
        return false;
    }
}

function get_records_sql_menu($sql) {
// Given an SQL select, this function returns an associative 
// array of the first two columns.  This is most useful in 
// combination with the choose_from_menu function to create 
// a form menu.

    global $db;

    $rs = $db->Execute("$sql");
    if (!$rs) return false;

    if ( $rs->RecordCount() > 0 ) {
        while (!$rs->EOF) {
            $menu[$rs->fields[0]] = $rs->fields[1];
            $rs->MoveNext();
        }
        return $menu;
        
    } else {
        return false;
    }
}

function get_field($table, $return, $field, $value) {
/// Get a single field from a database record

    global $db, $CFG;

    $rs = $db->Execute("SELECT $return FROM $CFG->prefix$table WHERE $field = '$value'");
    if (!$rs) return false;

    if ( $rs->RecordCount() == 1 ) {
        return $rs->fields["$return"];
    } else {
        return false;
    }
}

function set_field($table, $newfield, $newvalue, $field, $value) {
/// Set a single field in a database record

    global $db, $CFG;

    return $db->Execute("UPDATE $CFG->prefix$table SET $newfield = '$newvalue' WHERE $field = '$value'");
}


function delete_records($table, $field="", $value="", $field2="", $value2="", $field3="", $value3="") {
/// Delete one or more records from a table

    global $db, $CFG;

    if ($field and $value) {
        $select = "WHERE $field = '$value'";
        if ($field2 and $value2) {
            $select .= " AND $field2 = '$value2'";
            if ($field3 and $value3) {
                $select .= " AND $field3 = '$value3'";
            }
        }
    }

    return $db->Execute("DELETE FROM $CFG->prefix$table $select");
}


function insert_record($table, $dataobject, $returnid=true) {
/// Insert a record into a table and return the "id" field if required
/// If the return ID isn't required, then this just reports success as true/false.
/// $dataobject is an object containing needed data

    global $db, $CFG;

    // Determine all the fields needed
    if (! $columns = $db->MetaColumns("$CFG->prefix$table")) {
        return false;
    }

    $data = (array)$dataobject;

    // Pull out data matching these fields
    foreach ($columns as $column) {
        if ($column->name <> "id" && isset($data[$column->name]) ) {
            $ddd[$column->name] = $data[$column->name];
        }
    }

    // Construct SQL queries
    if (! $numddd = count($ddd)) {
        return false;
    }

    $count = 0;
    $inscolumns = "";
    $insvalues = "";
    $select = "";

    foreach ($ddd as $key => $value) {
        $count++;
        $inscolumns .= "$key";
        $insvalues .= "'$value'";
        $select .= "$key = '$value'";
        if ($count < $numddd) {
            $inscolumns .= ", ";
            $insvalues .= ", ";
            $select .= " AND ";
        }
    }

    if (! $rs = $db->Execute("INSERT INTO $CFG->prefix$table ($inscolumns) VALUES ($insvalues)")) {
        return false;
    }

    if ($returnid) {
        // Pull it out again to find the id.  This is the most cross-platform method.
        if ($rs = $db->Execute("SELECT id FROM $CFG->prefix$table WHERE $select")) {
            return $rs->fields[0];
        } else {
            return false;
        }
    } else {
        return true;
    }
}


function update_record($table, $dataobject) {
/// Update a record in a table
/// $dataobject is an object containing needed data

    global $db, $CFG;

    if (! isset($dataobject->id) ) {
        return false;
    }

    // Determine all the fields in the table
    if (!$columns = $db->MetaColumns("$CFG->prefix$table")) {
        return false;
    }
    $data = (array)$dataobject;

    // Pull out data matching these fields
    foreach ($columns as $column) {
        if ($column->name <> "id" && isset($data[$column->name]) ) {
            $ddd[$column->name] = $data[$column->name];
        }
    }

    // Construct SQL queries
    $numddd = count($ddd);
    $count = 0;
    $update = "";

    foreach ($ddd as $key => $value) {
        $count++;
        $update .= "$key = '$value'";
        if ($count < $numddd) {
            $update .= ", ";
        }
    }

    if ($rs = $db->Execute("UPDATE $CFG->prefix$table SET $update WHERE id = '$dataobject->id'")) {
        return true;
    } else {
        return false;
    }
}


function print_object($object) {
/// Mostly just for debugging

    $array = (array)$object;
    foreach ($array as $key => $item) {
        echo "$key -> $item <BR>";
    }
}




/// USER DATABASE ////////////////////////////////////////////////

function get_user_info_from_db($field, $value) {
/// Get a complete user record, which includes all the info 
/// in the user record, as well as membership information
/// Suitable for setting as $USER session cookie.

    global $db, $CFG;

    if (!$field || !$value) 
        return false;

    if (! $result = $db->Execute("SELECT * FROM {$CFG->prefix}user WHERE $field = '$value' AND deleted <> '1'")) {
        error("Could not find any active users!");
    }

    if ( $result->RecordCount() == 1 ) {
        $user = (object)$result->fields;

        $rs = $db->Execute("SELECT course FROM {$CFG->prefix}user_students WHERE user = '$user->id' ");
        while (!$rs->EOF) {
            $course = $rs->fields["course"];
            $user->student["$course"] = true;
            $rs->MoveNext();
        }

        $rs = $db->Execute("SELECT course FROM {$CFG->prefix}user_teachers WHERE user = '$user->id' ");
        while (!$rs->EOF) {
            $course = $rs->fields["course"];
            $user->teacher["$course"] = true;
            $rs->MoveNext();
        }

        $rs = $db->Execute("SELECT * FROM {$CFG->prefix}user_admins WHERE user = '$user->id' ");
        while (!$rs->EOF) {
            $user->admin = true;
            $rs->MoveNext();
        }

        if ($course = get_site()) {
            // Everyone is always a member of the top course
            $user->student["$course->id"] = true;
        }

        return $user;

    } else {
        return false;
    }
}

function update_user_in_db() {
/// Updates user record to record their last access

   global $db, $USER, $REMOTE_ADDR, $CFG;

   if (!isset($USER->id)) 
       return false;

   $timenow = time();
   if ($db->Execute("UPDATE {$CFG->prefix}user SET lastIP='$REMOTE_ADDR', lastaccess='$timenow' 
                     WHERE id = '$USER->id' ")) {
       return true;
   } else {
       return false;
   }
}


function adminlogin($username, $md5password) {
/// Does this username and password specify a valid admin user?

    global $CFG;

    return record_exists_sql("SELECT u.id FROM {$CFG->prefix}user u, {$CFG->prefix}user_admins a 
                              WHERE u.id = a.user 
                                AND u.username = '$username' 
                                AND u.password = '$md5password'");
}


function get_site () {
/// Returns $course object of the top-level site.

    if ( $course = get_record("course", "category", 0)) {
        return $course;
    } else {
        return false;
    }
}

function get_admin () {
/// Returns $user object of the main admin user

    global $CFG;

    if ( $admins = get_admins() ) {
        foreach ($admins as $admin) {
            return $admin;   // ie the first one 
        }
    } else {
        return false;
    }
}

function get_admins() {
/// Returns list of all admins

    global $CFG;

    return get_records_sql("SELECT u.* FROM {$CFG->prefix}user u, {$CFG->prefix}user_admins a
                            WHERE a.user = u.id
                            ORDER BY u.id ASC");
}


function get_teacher($courseid) {
/// Returns $user object of the main teacher for a course

    global $CFG;

    if ( $teachers = get_course_teachers($courseid, "t.authority ASC")) {
        foreach ($teachers as $teacher) {
            if ($teacher->authority) {
                return $teacher;   // the highest authority teacher
            }
        }
    } else {
        return false;
    }
}

function get_course_students($courseid, $sort="u.lastaccess DESC") {
/// Returns list of all students in this course

    global $CFG;

    return get_records_sql("SELECT u.* FROM {$CFG->prefix}user u, {$CFG->prefix}user_students s
                            WHERE s.course = '$courseid' AND s.user = u.id AND u.deleted = '0'
                            ORDER BY $sort");
}

function get_course_teachers($courseid, $sort="t.authority ASC") {
/// Returns list of all teachers in this course

    global $CFG;

    return get_records_sql("SELECT u.*,t.authority,t.role FROM {$CFG->prefix}user u, {$CFG->prefix}user_teachers t
                            WHERE t.course = '$courseid' AND t.user = u.id AND u.deleted = '0'
                            ORDER BY $sort");
}

function get_course_users($courseid, $sort="u.lastaccess DESC") {
/// Using this method because the direct SQL just would not always work!

    $teachers = get_course_teachers($courseid, $sort);
    $students = get_course_students($courseid, $sort);

    if ($teachers and $students) {
        return array_merge($teachers, $students);
    } else if ($teachers) {
        return $teachers;
    } else {
        return $students;
    }

///    return get_records_sql("SELECT u.* FROM user u, user_students s, user_teachers t
///                            WHERE (s.course = '$courseid' AND s.user = u.id) OR 
///                                  (t.course = '$courseid' AND t.user = u.id)
///                            ORDER BY $sort");
}



/// MODULE FUNCTIONS /////////////////////////////////////////////////

function get_coursemodule_from_instance($modulename, $instance, $courseid) {
/// Given an instance of a module, finds the coursemodule description

    global $CFG;

    return get_record_sql("SELECT cm.*, m.name
                           FROM {$CFG->prefix}course_modules cm, {$CFG->prefix}modules md, {$CFG->prefix}$modulename m 
                           WHERE cm.course = '$courseid' AND 
                                 cm.deleted = '0' AND
                                 cm.instance = m.id AND 
                                 md.name = '$modulename' AND 
                                 md.id = cm.module AND
                                 m.id = '$instance'");

}

function get_all_instances_in_course($modulename, $courseid, $sort="cw.section") {
/// Returns an array of all the active instances of a particular
/// module in a given course.   Returns false on any errors.

    global $CFG;

    return get_records_sql("SELECT m.*,cw.section,cm.id as coursemodule 
                            FROM {$CFG->prefix}course_modules cm, {$CFG->prefix}course_sections cw, 
                                 {$CFG->prefix}modules md, {$CFG->prefix}$modulename m 
                            WHERE cm.course = '$courseid' AND 
                                  cm.instance = m.id AND 
                                  cm.deleted = '0' AND
                                  cm.section = cw.id AND 
                                  md.name = '$modulename' AND 
                                  md.id = cm.module
                            ORDER BY $sort");

}

?>