MDL-17522 improved dml tests, fixed sql LIMIT support in native drivers

lib/dml/moodle_database.php

@@ -557,7 +557,7 @@ abstract class moodle_database {
                 return array($sql, array_values($params), SQL_PARAMS_QM); // 0-based required
             } else if ($target_type & SQL_PARAMS_NAMED) {
                 $finalparams = array();
-                $pname = 'param00000';
+                $pname = 'param0';
                 $parts = explode('?', $sql);
                 $sql = array_shift($parts);
                 foreach ($parts as $part) {

lib/dml/mysqli_native_moodle_database.php

@@ -477,6 +477,9 @@ class mysqli_native_moodle_database extends moodle_database {
     public function get_recordset_sql($sql, array $params=null, $limitfrom=0, $limitnum=0) {
         $limitfrom = (int)$limitfrom;
         $limitnum  = (int)$limitnum;
+        $limitfrom = ($limitfrom < 0) ? 0 : $limitfrom;
+        $limitnum  = ($limitnum < 0)  ? 0 : $limitnum;
+
         if ($limitfrom or $limitnum) {
             if ($limitnum < 1) {
                 $limitnum = "18446744073709551615";
@@ -516,6 +519,9 @@ class mysqli_native_moodle_database extends moodle_database {
     public function get_records_sql($sql, array $params=null, $limitfrom=0, $limitnum=0) {
         $limitfrom = (int)$limitfrom;
         $limitnum  = (int)$limitnum;
+        $limitfrom = ($limitfrom < 0) ? 0 : $limitfrom;
+        $limitnum  = ($limitnum < 0)  ? 0 : $limitnum;
+
         if ($limitfrom or $limitnum) {
             if ($limitnum < 1) {
                 $limitnum = "18446744073709551615";

lib/dml/pgsql_native_moodle_database.php

@@ -545,6 +545,8 @@ class pgsql_native_moodle_database extends moodle_database {
     public function get_recordset_sql($sql, array $params=null, $limitfrom=0, $limitnum=0) {
         $limitfrom = (int)$limitfrom;
         $limitnum  = (int)$limitnum;
+        $limitfrom = ($limitfrom < 0) ? 0 : $limitfrom;
+        $limitnum  = ($limitnum < 0)  ? 0 : $limitnum;
         if ($limitfrom or $limitnum) {
             if ($limitnum < 1) {
                 $limitnum = "18446744073709551615";
@@ -582,6 +584,8 @@ class pgsql_native_moodle_database extends moodle_database {
     public function get_records_sql($sql, array $params=null, $limitfrom=0, $limitnum=0) {
         $limitfrom = (int)$limitfrom;
         $limitnum  = (int)$limitnum;
+        $limitfrom = ($limitfrom < 0) ? 0 : $limitfrom;
+        $limitnum  = ($limitnum < 0)  ? 0 : $limitnum;
         if ($limitfrom or $limitnum) {
             if ($limitnum < 1) {
                 $limitnum = "18446744073709551615";