Index: class.ux_t3lib_sqlparser.php
===================================================================
--- class.ux_t3lib_sqlparser.php	(revision 26756)
+++ class.ux_t3lib_sqlparser.php	(working copy)
@@ -535,7 +535,8 @@
 								$indexKeys = array_merge($indexKeys, $GLOBALS['TYPO3_DB']->handlerInstance[$GLOBALS['TYPO3_DB']->handler_getFromTableList($components['TABLE'])]->DataDictionary->CreateIndexSQL($n, $components['TABLE'], $field, array('UNIQUE')));
 							}
 						} else {
-							$indexKeys = array_merge($indexKeys, $GLOBALS['TYPO3_DB']->handlerInstance[$GLOBALS['TYPO3_DB']->handler_getFromTableList($components['TABLE'])]->DataDictionary->CreateIndexSQL($components['TABLE'] . '_' . $kN, $components['TABLE'], $kCfg));
+							$indexName = $GLOBALS['TYPO3_DB']->automap_indexName($components['TABLE'], $components['TABLE'] . '_' . $kN);
+							$indexKeys = array_merge($indexKeys, $GLOBALS['TYPO3_DB']->handlerInstance[$GLOBALS['TYPO3_DB']->handler_getFromTableList($components['TABLE'])]->DataDictionary->CreateIndexSQL($indexName, $components['TABLE'], $kCfg));
 						}
 					}
 				}
Index: class.ux_t3lib_db.php
===================================================================
--- class.ux_t3lib_db.php	(revision 26756)
+++ class.ux_t3lib_db.php	(working copy)
@@ -2637,6 +2637,30 @@
 		}
 	}
 
+	/**
+	 * Automatically re-mapping index name if needed.
+	 * 
+	 * @param string $table Table name
+	 * @param string $indexName initial index name
+	 * @return string Either $indexName or an automatically remapped string to be compatible with the underlying DBMS
+	 */
+	public function automap_indexName($table, $indexName) {
+		$handlerCfg = $this->handlerCfg[$this->handler_getFromTableList($table)]; 
+		switch ((string)$handlerCfg['type']) {
+			case 'native':
+				return $indexName;
+			case 'adodb':
+				switch ((string)$handlerCfg['config']['driver']) {
+					case 'oci8':
+							// Oracle only support up to 30-character identifier
+						if (strlen($indexName) > 30) {
+							return substr(md5($indexName), 0, 30);
+						}
+						break;
+				}
+		}
+		return $indexName;
+	}
 
 
 
@@ -2653,6 +2677,7 @@
 
 
 
+
 	/**************************************
 	*
 	* Debugging
Index: tests/db_oracle_testcase.php
===================================================================
--- tests/db_oracle_testcase.php	(revision 26757)
+++ tests/db_oracle_testcase.php	(working copy)
@@ -390,5 +390,45 @@
 		$expected .= ' AND "pages"."deleted" = 0 AND 1 = 1 ORDER BY "cpg_categories"."pos"';
 		$this->assertEquals($expected, $query);
 	}
+
+	/**
+	 * @test
+	 * @see http://bugs.typo3.org/view.php?id=3751
+	 */
+	public function longIndexesAreAutomaticallyRemapped() {
+		$parseString = '
+			CREATE TABLE tx_realurl_uniqalias (
+				uid int(11) NOT NULL auto_increment,
+				tstamp int(11) DEFAULT \'0\' NOT NULL,
+				tablename varchar(60) DEFAULT \'\' NOT NULL,
+				field_alias varchar(255) DEFAULT \'\' NOT NULL,
+				field_id varchar(60) DEFAULT \'\' NOT NULL,
+				value_alias varchar(255) DEFAULT \'\' NOT NULL,
+				value_id int(11) DEFAULT \'0\' NOT NULL,
+				lang int(11) DEFAULT \'0\' NOT NULL,
+				expire int(11) DEFAULT \'0\' NOT NULL,
+
+				PRIMARY KEY (uid),
+				KEY tablename (tablename),
+				KEY bk_realurl01 (field_alias,field_id,value_id,lang,expire),
+				KEY bk_realurl02 (tablename,field_alias,field_id,value_alias(220),expire)
+			);
+		';
+
+		$components = $GLOBALS['TYPO3_DB']->SQLparser->_callRef('parseCREATETABLE', $parseString);
+		$sqlCommands = $GLOBALS['TYPO3_DB']->SQLparser->_call('compileCREATETABLE', $components);
+		$this->assertEquals(
+			'CREATE INDEX "tx_realurl_uniqalias_tablename" ON "tx_realurl_uniqalias" ("tablename")',
+			$this->cleanSql($sqlCommands[1])
+		);
+		$this->assertEquals(
+			'CREATE INDEX "' . substr(md5('tx_realurl_uniqalias_bk_realurl01'), 0, 30) . '" ON "tx_realurl_uniqalias" ("field_alias", "field_id", "value_id", "lang", "expire")',
+			$this->cleanSql($sqlCommands[2])
+		);
+		$this->assertEquals(
+			'CREATE INDEX "' . substr(md5('tx_realurl_uniqalias_bk_realurl02'), 0, 30) . '" ON "tx_realurl_uniqalias" ("tablename", "field_alias", "field_id", "value_alias", "expire")',
+			$this->cleanSql($sqlCommands[3])
+		);
+	}
 }
 ?>
\ No newline at end of file