+ * Fetches the first row
+ *
+ * Please use dba::selectFirst or dba::exists whenever this is possible.
+ *
+ * @brief Fetches the first row
+ * @param string $sql SQL statement
+ * @return array first row of query
+ */
+ public static function fetch_first($sql) {
+ $params = self::getParam(func_get_args());
+
+ $stmt = self::p($sql, $params);
+
+ if (is_bool($stmt)) {
+ $retval = $stmt;
+ } else {
+ $retval = self::fetch($stmt);
+ }
+
+ self::close($stmt);
+
+ return $retval;
+ }
+
+ /**
+ * @brief Returns the number of affected rows of the last statement
+ *
+ * @return int Number of rows
+ */
+ public static function affected_rows() {
+ return self::$affected_rows;
+ }
+
+ /**
+ * @brief Returns the number of columns of a statement
+ *
+ * @param object Statement object
+ * @return int Number of columns
+ */
+ public static function columnCount($stmt) {
+ if (!is_object($stmt)) {
+ return 0;
+ }
+ switch (self::$driver) {
+ case 'pdo':
+ return $stmt->columnCount();
+ case 'mysqli':
+ return $stmt->field_count;
+ }
+ return 0;
+ }
+ /**
+ * @brief Returns the number of rows of a statement
+ *
+ * @param PDOStatement|mysqli_result|mysqli_stmt Statement object
+ * @return int Number of rows
+ */
+ public static function num_rows($stmt) {
+ if (!is_object($stmt)) {
+ return 0;
+ }
+ switch (self::$driver) {
+ case 'pdo':
+ return $stmt->rowCount();
+ case 'mysqli':
+ return $stmt->num_rows;
+ }
+ return 0;
+ }
+
+ /**
+ * @brief Fetch a single row
+ *
+ * @param PDOStatement|mysqli_result|mysqli_stmt $stmt statement object
+ * @return array current row
+ */
+ public static function fetch($stmt) {
+ if (!is_object($stmt)) {
+ return false;
+ }
+
+ switch (self::$driver) {
+ case 'pdo':
+ return $stmt->fetch(PDO::FETCH_ASSOC);
+ case 'mysqli':
+ if (get_class($stmt) == 'mysqli_result') {
+ return $stmt->fetch_assoc();
+ }
+
+ // This code works, but is slow
+
+ // Bind the result to a result array
+ $cols = array();
+
+ $cols_num = array();
+ for ($x = 0; $x < $stmt->field_count; $x++) {
+ $cols[] = &$cols_num[$x];
+ }
+
+ call_user_func_array(array($stmt, 'bind_result'), $cols);
+
+ if (!$stmt->fetch()) {
+ return false;
+ }
+
+ // The slow part:
+ // We need to get the field names for the array keys
+ // It seems that there is no better way to do this.
+ $result = $stmt->result_metadata();
+ $fields = $result->fetch_fields();
+
+ $columns = array();
+ foreach ($cols_num AS $param => $col) {
+ $columns[$fields[$param]->name] = $col;
+ }
+ return $columns;
+ }
+ }
+
+ /**
+ * @brief Insert a row into a table
+ *
+ * @param string $table Table name
+ * @param array $param parameter array
+ * @param bool $on_duplicate_update Do an update on a duplicate entry
+ *
+ * @return boolean was the insert successfull?
+ */
+ public static function insert($table, $param, $on_duplicate_update = false) {
+
+ if (empty($table) || empty($param)) {
+ logger('Table and fields have to be set');
+ return false;
+ }
+
+ $sql = "INSERT INTO `".self::escape($table)."` (`".implode("`, `", array_keys($param))."`) VALUES (".
+ substr(str_repeat("?, ", count($param)), 0, -2).")";
+
+ if ($on_duplicate_update) {
+ $sql .= " ON DUPLICATE KEY UPDATE `".implode("` = ?, `", array_keys($param))."` = ?";
+
+ $values = array_values($param);
+ $param = array_merge_recursive($values, $values);
+ }
+
+ return self::e($sql, $param);
+ }
+
+ /**
+ * @brief Fetch the id of the last insert command
+ *
+ * @return integer Last inserted id
+ */
+ public static function lastInsertId() {
+ switch (self::$driver) {
+ case 'pdo':
+ $id = self::$db->lastInsertId();
+ break;
+ case 'mysqli':
+ $id = self::$db->insert_id;
+ break;
+ }
+ return $id;
+ }
+
+ /**
+ * @brief Locks a table for exclusive write access
+ *
+ * This function can be extended in the future to accept a table array as well.
+ *
+ * @param string $table Table name
+ *
+ * @return boolean was the lock successful?
+ */
+ public static function lock($table) {
+ // See here: https://dev.mysql.com/doc/refman/5.7/en/lock-tables-and-transactions.html
+ self::e("SET autocommit=0");
+ $success = self::e("LOCK TABLES `".self::escape($table)."` WRITE");
+ if (!$success) {
+ self::e("SET autocommit=1");
+ } else {
+ self::$in_transaction = true;
+ }
+ return $success;
+ }
+
+ /**
+ * @brief Unlocks all locked tables
+ *
+ * @return boolean was the unlock successful?
+ */
+ public static function unlock() {
+ // See here: https://dev.mysql.com/doc/refman/5.7/en/lock-tables-and-transactions.html
+ self::e("COMMIT");
+ $success = self::e("UNLOCK TABLES");
+ self::e("SET autocommit=1");
+ self::$in_transaction = false;
+ return $success;
+ }
+
+ /**
+ * @brief Starts a transaction
+ *
+ * @return boolean Was the command executed successfully?
+ */
+ public static function transaction() {
+ if (!self::e('COMMIT')) {
+ return false;
+ }
+ if (!self::e('START TRANSACTION')) {
+ return false;
+ }
+ self::$in_transaction = true;
+ return true;
+ }
+
+ /**
+ * @brief Does a commit
+ *
+ * @return boolean Was the command executed successfully?
+ */
+ public static function commit() {
+ if (!self::e('COMMIT')) {
+ return false;
+ }
+ self::$in_transaction = false;
+ return true;
+ }
+
+ /**
+ * @brief Does a rollback
+ *
+ * @return boolean Was the command executed successfully?
+ */
+ public static function rollback() {
+ if (!self::e('ROLLBACK')) {
+ return false;
+ }
+ self::$in_transaction = false;
+ return true;
+ }
+
+ /**
+ * @brief Build the array with the table relations
+ *
+ * The array is build from the database definitions in DBStructure.php
+ *
+ * This process must only be started once, since the value is cached.
+ */
+ private static function build_relation_data() {
+ $definition = DBStructure::definition();
+
+ foreach ($definition AS $table => $structure) {
+ foreach ($structure['fields'] AS $field => $field_struct) {
+ if (isset($field_struct['relation'])) {
+ foreach ($field_struct['relation'] AS $rel_table => $rel_field) {
+ self::$relation[$rel_table][$rel_field][$table][] = $field;
+ }
+ }
+ }
+ }
+ }
+
+ /**
+ * @brief Delete a row from a table
+ *
+ * @param string $table Table name
+ * @param array $conditions Field condition(s)
+ * @param boolean $in_process Internal use: Only do a commit after the last delete
+ * @param array $callstack Internal use: prevent endless loops
+ *
+ * @return boolean|array was the delete successful? When $in_process is set: deletion data
+ */
+ public static function delete($table, array $conditions, $in_process = false, array &$callstack = [])
+ {
+ if (empty($table) || empty($conditions)) {
+ logger('Table and conditions have to be set');
+ return false;
+ }
+
+ $commands = [];
+
+ // Create a key for the loop prevention
+ $key = $table . ':' . implode(':', array_keys($conditions)) . ':' . implode(':', $conditions);
+
+ // We quit when this key already exists in the callstack.
+ if (isset($callstack[$key])) {
+ return $commands;
+ }
+
+ $callstack[$key] = true;
+
+ $table = self::escape($table);
+
+ $commands[$key] = ['table' => $table, 'conditions' => $conditions];
+
+ // To speed up the whole process we cache the table relations
+ if (count(self::$relation) == 0) {
+ self::build_relation_data();
+ }
+
+ // Is there a relation entry for the table?
+ if (isset(self::$relation[$table])) {
+ // We only allow a simple "one field" relation.
+ $field = array_keys(self::$relation[$table])[0];
+ $rel_def = array_values(self::$relation[$table])[0];
+
+ // Create a key for preventing double queries
+ $qkey = $field . '-' . $table . ':' . implode(':', array_keys($conditions)) . ':' . implode(':', $conditions);
+
+ // When the search field is the relation field, we don't need to fetch the rows
+ // This is useful when the leading record is already deleted in the frontend but the rest is done in the backend
+ if ((count($conditions) == 1) && ($field == array_keys($conditions)[0])) {
+ foreach ($rel_def AS $rel_table => $rel_fields) {
+ foreach ($rel_fields AS $rel_field) {
+ $retval = self::delete($rel_table, array($rel_field => array_values($conditions)[0]), true, $callstack);
+ $commands = array_merge($commands, $retval);
+ }
+ }
+ // We quit when this key already exists in the callstack.
+ } elseif (!isset($callstack[$qkey])) {
+
+ $callstack[$qkey] = true;
+
+ // Fetch all rows that are to be deleted
+ $data = self::select($table, array($field), $conditions);
+
+ while ($row = self::fetch($data)) {
+ // Now we accumulate the delete commands
+ $retval = self::delete($table, array($field => $row[$field]), true, $callstack);
+ $commands = array_merge($commands, $retval);
+ }
+
+ self::close($data);
+
+ // Since we had split the delete command we don't need the original command anymore
+ unset($commands[$key]);
+ }
+ }
+
+ if (!$in_process) {
+ // Now we finalize the process
+ $do_transaction = !self::$in_transaction;
+
+ if ($do_transaction) {
+ self::transaction();
+ }
+
+ $compacted = [];
+ $counter = [];
+
+ foreach ($commands AS $command) {
+ $conditions = $command['conditions'];
+ $array_element = each($conditions);
+ $array_key = $array_element['key'];
+ if (is_int($array_key)) {
+ $condition_string = " WHERE " . array_shift($conditions);
+ } else {
+ $condition_string = " WHERE `" . implode("` = ? AND `", array_keys($conditions)) . "` = ?";
+ }
+
+ if ((count($command['conditions']) > 1) || is_int($array_key)) {
+ $sql = "DELETE FROM `" . $command['table'] . "`" . $condition_string;
+ logger(self::replace_parameters($sql, $conditions), LOGGER_DATA);
+
+ if (!self::e($sql, $conditions)) {
+ if ($do_transaction) {
+ self::rollback();
+ }
+ return false;
+ }
+ } else {
+ $key_table = $command['table'];
+ $key_condition = array_keys($command['conditions'])[0];
+ $value = array_values($command['conditions'])[0];
+
+ // Split the SQL queries in chunks of 100 values
+ // We do the $i stuff here to make the code better readable
+ $i = $counter[$key_table][$key_condition];
+ if (count($compacted[$key_table][$key_condition][$i]) > 100) {
+ ++$i;
+ }
+
+ $compacted[$key_table][$key_condition][$i][$value] = $value;
+ $counter[$key_table][$key_condition] = $i;
+ }
+ }
+ foreach ($compacted AS $table => $values) {
+ foreach ($values AS $field => $field_value_list) {
+ foreach ($field_value_list AS $field_values) {
+ $sql = "DELETE FROM `" . $table . "` WHERE `" . $field . "` IN (" .
+ substr(str_repeat("?, ", count($field_values)), 0, -2) . ");";
+
+ logger(self::replace_parameters($sql, $field_values), LOGGER_DATA);
+
+ if (!self::e($sql, $field_values)) {
+ if ($do_transaction) {
+ self::rollback();
+ }
+ return false;
+ }
+ }
+ }
+ }
+ if ($do_transaction) {
+ self::commit();
+ }
+ return true;
+ }
+
+ return $commands;
+ }
+
+ /**
+ * @brief Updates rows
+ *
+ * Updates rows in the database. When $old_fields is set to an array,
+ * the system will only do an update if the fields in that array changed.
+ *
+ * Attention:
+ * Only the values in $old_fields are compared.
+ * This is an intentional behaviour.
+ *
+ * Example:
+ * We include the timestamp field in $fields but not in $old_fields.
+ * Then the row will only get the new timestamp when the other fields had changed.
+ *
+ * When $old_fields is set to a boolean value the system will do this compare itself.
+ * When $old_fields is set to "true" the system will do an insert if the row doesn't exists.
+ *
+ * Attention:
+ * Only set $old_fields to a boolean value when you are sure that you will update a single row.
+ * When you set $old_fields to "true" then $fields must contain all relevant fields!