Merge pull request #7 from LionsAd/issue-3280696--use-default-on-null

Issue #3280696: Use DEFAULT ON NULL instead of the defaults trigger

Schema.php

@@ -163,57 +163,6 @@ EOF;
     return $key;
   }
 
-  /**
-   * Emulates mysql default column behaviour.
-   *
-   * Eg. insert into table (col1) values (null).
-   * If col1 has default in mysql you have the default inserted instead of null.
-   * On oracle you have null inserted. So we need a trigger to intercept this
-   * condition and substitute null with default. This happens on MySQL only
-   * inserting not updating.
-   */
-  public function rebuildDefaultsTrigger($table) {
-    $schema = $this->tableSchema($this->connection->prefixTables('{' . $table . '}'));
-    $oname = $this->oid($table, FALSE, FALSE);
-
-    $trigger = 'create or replace trigger ' . $this->oid('TRG_' . $table . '_DEFS', TRUE) .
-      ' before insert on ' . $this->oid($table, TRUE) .
-      ' for each row begin /* defs trigger */ if inserting then ';
-
-    $serial_oname = $this->connection->queryOracle("select field_name from table(identifier.get_serial(?,?))", array($table, $schema))->fetchColumn();
-    $serial_oname = $serial_oname ? $serial_oname : "^NNC^";
-
-    $stmt = $this->connection->queryOracle(
-      "select /*+ALL_ROWS*/ column_name,
-       data_default
-       from all_tab_columns
-       where column_name != ?
-       and owner= nvl(user,?)
-       and table_name= ?
-       and data_default is not null
-      ",
-      array($serial_oname, $schema, $oname)
-    );
-
-    $def = FALSE;
-
-    while ($row = $stmt->fetchObject()) {
-      $def = TRUE;
-      $trigger .=
-        'if :NEW."' . $row->column_name . '" is null or to_char(:NEW."' . $row->column_name . '") = \'' . ORACLE_EMPTY_STRING_REPLACER . '\'
-          then :NEW."' . $row->column_name . '":= ' . $row->data_default . ';
-          end if;
-        ';
-    }
-
-    if (!$def) {
-      $trigger .= ' null; ';
-    }
-
-    $trigger .= 'end if; end;';
-    $this->connection->query($trigger, [], ['allow_delimiter_in_query' => TRUE]);
-  }
-
   /**
    * {@inheritdoc}
    */
@@ -225,7 +174,6 @@ EOF;
     foreach ($statements as $statement) {
       $this->connection->query($statement, [], ['allow_delimiter_in_query' => TRUE]);
     }
-    $this->rebuildDefaultsTrigger($name);
     $this->resetLongIdentifiers();
     $this->resetTableInformation($name);
   }
@@ -309,10 +257,6 @@ EOF;
     $oname = $this->oid($name);
     $sql = $oname . ' ' . $spec['oracle_type'];
 
-    if (isset($spec['type']) && $spec['type'] == 'serial') {
-      unset($spec['not null']);
-    }
-
     if ($spec['oracle_type'] == 'VARCHAR2') {
       $sql .= '(' . (!empty($spec['length']) ? $spec['length'] : ORACLE_MAX_VARCHAR2_LENGTH) . ' CHAR)';
     }
@@ -328,15 +272,20 @@ EOF;
       $sql .= '(' . $spec['precision'] . ', ' . $spec['scale'] . ')';
     }
 
+    // DEFAULT ON NULL implies NOT NULL.
+    $on_null = '';
+    if (!empty($spec['not null'])) {
+      $on_null = 'ON NULL ';
+    }
+
     if (isset($spec['identity'])) {
-      $sql .= " GENERATED BY DEFAULT ON NULL AS IDENTITY";
+      $sql .= " GENERATED BY DEFAULT " . $on_null . "AS IDENTITY";
     }
     elseif (isset($spec['default'])) {
       $default = is_string($spec['default']) ? $this->connection->quote($this->connection->cleanupArgValue($spec['default'])) : $spec['default'];
-      $sql .= " default {$default}";
+      $sql .= " DEFAULT " . $on_null . "{$default}";
     }
-
-    if (!empty($spec['not null'])) {
+    elseif (!empty($spec['not null'])) {
       $sql .= ' NOT NULL';
     }
 
@@ -687,15 +636,18 @@ EOF;
    * {@inheritdoc}
    */
   public function fieldSetDefault($table, $field, $default) {
+    $on_null = '';
     if (is_null($default)) {
       $default = 'NULL';
     }
     else {
+      // @todo There might be cases where the column is not actually NOT NULL,
+      //       but there is no way to know without looking at the Drupal schema.
+      $on_null = 'ON NULL ';
       $default = is_string($default) ? $this->connection->quote($this->connection->cleanupArgValue($default)) : $default;
     }
 
-    $this->connection->query('ALTER TABLE ' . $this->oid($table, TRUE) . ' MODIFY (' . $this->oid($field) . ' DEFAULT ' . $default . ' )');
-    $this->rebuildDefaultsTrigger($table);
+    $this->connection->query('ALTER TABLE ' . $this->oid($table, TRUE) . ' MODIFY (' . $this->oid($field) . ' DEFAULT ' . $on_null . $default . ' )');
   }
 
   /**
@@ -703,7 +655,6 @@ EOF;
    */
   public function fieldSetNoDefault($table, $field) {
     $this->connection->query('ALTER TABLE ' . $this->oid($table, TRUE) . ' MODIFY (' . $this->oid($field) . ' DEFAULT NULL)');
-    $this->rebuildDefaultsTrigger($table);
   }
 
   /**
@@ -1216,7 +1167,6 @@ EOF;
 
     $this->resetLongIdentifiers();
     $this->resetTableInformation($cache_table);
-    $this->rebuildDefaultsTrigger($trigger_table);
   }
 
 }