MDL-32113 xmldb: Support numeric fields with precision up to 38 digits

The patch increases the maximum supported precision (total number of
digits) for numeric (decimal) fields to 38 digits (current limit on
Oracle and MSSQL).

Additionally, we add our own limit for the whole number part of numeric
fields so they are no longer than integer fields (20 digits). This is to
make it easier to eventually convert from one field type to another.
Note that PHP floats commonly support precision of roughly 15 digits
anyway.

admin/tool/xmldb/actions/edit_field/edit_field.js

@@ -80,7 +80,7 @@ function transformForm(event) {
             decimalsField.value = '';
             break;
         case '2':  // XMLDB_TYPE_NUMBER
-            lengthTip.innerHTML = ' 1...20'; // Hardcoded xmldb_field::NUMBER_MAX_LENGTH, yes!
+            lengthTip.innerHTML = ' 1...38'; // Hardcoded xmldb_field::NUMBER_MAX_LENGTH, yes!
             lengthField.disabled = false;
             decimalsTip.innerHTML = ' 0...length or empty';
             break;

admin/tool/xmldb/actions/edit_field_save/edit_field_save.class.php

@@ -48,6 +48,7 @@ function init() {
             'floatincorrectlength' => 'tool_xmldb',
             'charincorrectlength' => 'tool_xmldb',
             'numberincorrectdecimals' => 'tool_xmldb',
+            'numberincorrectwholepart' => 'tool_xmldb',
             'floatincorrectdecimals' => 'tool_xmldb',
             'defaultincorrect' => 'tool_xmldb',
             'back' => 'tool_xmldb',
@@ -158,6 +159,9 @@ function invoke() {
                                        $decimals < $length))) {
                 $errors[] = $this->str['numberincorrectdecimals'];
             }
+            if (!empty($decimals) && ($length - $decimals > xmldb_field::INTEGER_MAX_LENGTH)) {
+                $errors[] = $this->str['numberincorrectwholepart'];
+            }
             if (!(empty($default) || (is_numeric($default) &&
                                        !empty($default)))) {
                 $errors[] = $this->str['defaultincorrect'];

admin/tool/xmldb/lang/en/tool_xmldb.php

@@ -165,6 +165,7 @@
 $string['nowrongoraclesemanticsfound'] = 'No Oracle columns using BYTE semantics have been found, your DB doesn\'t need further actions.';
 $string['numberincorrectdecimals'] = 'Incorrect number of decimals for number field';
 $string['numberincorrectlength'] = 'Incorrect length for number field';
+$string['numberincorrectwholepart'] = 'Too big whole number part for number field';
 $string['pendingchanges'] = 'Note: You have performed changes to this file. They can be saved at any moment.';
 $string['pendingchangescannotbesaved'] = 'There are changes in this file but they cannot be saved! Please verify that both the directory and the "install.xml" within it have write permissions for the web server.';
 $string['pendingchangescannotbesavedreload'] = 'There are changes in this file but they cannot be saved! Please verify that both the directory and the "install.xml" within it have write permissions for the web server. Then reload this page and you should be able to save those changes.';

lib/upgrade.txt

@@ -1,7 +1,14 @@
 This files describes API changes in core libraries and APIs,
 information provided here is intended especially for developers.
 
+=== 3.5 ===
+
+* The maximum supported precision (the total number of digits) for XMLDB_TYPE_NUMBER ("number") fields raised from 20 to
+  38 digits. Additionally, the whole number part (precision minus scale) must not be longer than the maximum length of
+  integer fields (20 digits). Note that PHP floats commonly support precision of roughly 15 digits only (MDL-32113).
+
 === 3.4 ===
+
 * oauth2_client::request method has an extra parameter to specify the accept header for the response (MDL-60733)
 * The following functions, previously used (exclusively) by upgrade steps are not available
   anymore because of the upgrade cleanup performed for this version. See MDL-57432 for more info:

lib/xmldb/xmldb_field.php

@@ -64,9 +64,9 @@ class xmldb_field extends xmldb_object {
     const INTEGER_MAX_LENGTH = 20;
 
     /**
-     * @const max length of decimals
+     * @const max length (precision, the total number of digits) of decimals
      */
-    const NUMBER_MAX_LENGTH = 20;
+    const NUMBER_MAX_LENGTH = 38;
 
     /**
      * @const max length of floats
@@ -795,6 +795,10 @@ public function validateDefinition(xmldb_table $xmldb_table=null) {
                 if (!is_number($decimals) or $decimals < 0 or $decimals > $length) {
                     return 'Invalid field definition in table {'.$xmldb_table->getName().'}: XMLDB_TYPE_NUMBER field "'.$this->getName().'" has invalid decimals';
                 }
+                if ($length - $decimals > self::INTEGER_MAX_LENGTH) {
+                    return 'Invalid field definition in table {'.$xmldb_table->getName().'}: XMLDB_TYPE_NUMBER field "'.
+                        $this->getName().'" has too big whole number part';
+                }
                 $default = $this->getDefault();
                 if (!empty($default) and !is_numeric($default)) {
                     return 'Invalid field definition in table {'.$xmldb_table->getName().'}: XMLDB_TYPE_NUMBER field "'.$this->getName().'" has invalid default';