diff --git a/system/database/drivers/mssql/mssql_forge.php b/system/database/drivers/mssql/mssql_forge.php
index ddd1bb6..6995d34 100644
--- a/system/database/drivers/mssql/mssql_forge.php
+++ b/system/database/drivers/mssql/mssql_forge.php
@@ -147,16 +147,24 @@
 			$primary_keys = $this->db->_protect_identifiers($primary_keys);
 			$sql .= ",\n\tPRIMARY KEY (" . implode(', ', $primary_keys) . ")";
 		}
-
+		
 		if (is_array($keys) && count($keys) > 0)
 		{
-			$keys = $this->db->_protect_identifiers($keys);
 			foreach ($keys as $key)
 			{
-				$sql .= ",\n\tFOREIGN KEY ($key)";
+				if (is_array($key))
+				{
+					$key = $this->db->_protect_identifiers($key);	
+				}
+				else
+				{
+					$key = array($this->db->_protect_identifiers($key));
+				}
+				
+				$sql .= ",\n\tFOREIGN KEY (" . implode(', ', $key) . ")";
 			}
 		}
-
+		
 		$sql .= "\n)";
 
 		return $sql;
diff --git a/system/database/drivers/mysql/mysql_forge.php b/system/database/drivers/mysql/mysql_forge.php
index a631e43..28143a0 100644
--- a/system/database/drivers/mysql/mysql_forge.php
+++ b/system/database/drivers/mysql/mysql_forge.php
@@ -153,16 +153,27 @@
 
 		if (count($primary_keys) > 0)
 		{
+			$key_name = $this->db->_protect_identifiers(implode('_', $primary_keys));
 			$primary_keys = $this->db->_protect_identifiers($primary_keys);
-			$sql .= ",\n\tPRIMARY KEY (" . implode(', ', $primary_keys) . ")";
+			$sql .= ",\n\tPRIMARY KEY ".$key_name." (" . implode(', ', $primary_keys) . ")";
 		}
 
 		if (is_array($keys) && count($keys) > 0)
 		{
-			$keys = $this->db->_protect_identifiers($keys);
 			foreach ($keys as $key)
 			{
-				$sql .= ",\n\tKEY ($key)";
+				if (is_array($key))
+				{
+					$key_name = $this->db->_protect_identifiers(implode('_', $key));
+					$key = $this->db->_protect_identifiers($key);	
+				}
+				else
+				{
+					$key_name = $this->db->_protect_identifiers($key);
+					$key = array($key_name);
+				}
+				
+				$sql .= ",\n\tKEY {$key_name} (" . implode(', ', $key) . ")";
 			}
 		}
 
diff --git a/system/database/drivers/mysqli/mysqli_forge.php b/system/database/drivers/mysqli/mysqli_forge.php
index f767acb..da79bc6 100644
--- a/system/database/drivers/mysqli/mysqli_forge.php
+++ b/system/database/drivers/mysqli/mysqli_forge.php
@@ -153,16 +153,27 @@
 
 		if (count($primary_keys) > 0)
 		{
+			$key_name = $this->db->_protect_identifiers(implode('_', $primary_keys));
 			$primary_keys = $this->db->_protect_identifiers($primary_keys);
-			$sql .= ",\n\tPRIMARY KEY (" . implode(', ', $primary_keys) . ")";
+			$sql .= ",\n\tPRIMARY KEY ".$key_name." (" . implode(', ', $primary_keys) . ")";
 		}
 
 		if (is_array($keys) && count($keys) > 0)
 		{
-			$keys = $this->db->_protect_identifiers($keys);
 			foreach ($keys as $key)
 			{
-				$sql .= ",\n\tKEY ($key)";
+				if (is_array($key))
+				{
+					$key_name = $this->db->_protect_identifiers(implode('_', $key));
+					$key = $this->db->_protect_identifiers($key);	
+				}
+				else
+				{
+					$key_name = $this->db->_protect_identifiers($key);
+					$key = array($key_name);
+				}
+				
+				$sql .= ",\n\tKEY {$key_name} (" . implode(', ', $key) . ")";
 			}
 		}
 
diff --git a/system/database/drivers/oci8/oci8_forge.php b/system/database/drivers/oci8/oci8_forge.php
index 9f3fac5..6266c75 100644
--- a/system/database/drivers/oci8/oci8_forge.php
+++ b/system/database/drivers/oci8/oci8_forge.php
@@ -135,10 +135,21 @@
 			$sql .= ",\n\tPRIMARY KEY (" . implode(', ', $primary_keys) . ")";
 		}
 
-		if (count($keys) > 0)
+		if (is_array($keys) && count($keys) > 0)
 		{
-			$keys = $this->db->_protect_identifiers($keys);
-			$sql .= ",\n\tUNIQUE COLUMNS (" . implode(', ', $keys) . ")";
+			foreach ($keys as $key)
+			{
+				if (is_array($key))
+				{
+					$key = $this->db->_protect_identifiers($key);	
+				}
+				else
+				{
+					$key = array($this->db->_protect_identifiers($key));
+				}
+				
+				$sql .= ",\n\tUNIQUE COLUMNS (" . implode(', ', $key) . ")";
+			}
 		}
 		
 		$sql .= "\n)";
diff --git a/system/database/drivers/odbc/odbc_forge.php b/system/database/drivers/odbc/odbc_forge.php
index 60df616..10924ab 100644
--- a/system/database/drivers/odbc/odbc_forge.php
+++ b/system/database/drivers/odbc/odbc_forge.php
@@ -146,16 +146,24 @@
 			$primary_keys = $this->db->_protect_identifiers($primary_keys);
 			$sql .= ",\n\tPRIMARY KEY (" . implode(', ', $primary_keys) . ")";
 		}
-
+		
 		if (is_array($keys) && count($keys) > 0)
 		{
-			$keys = $this->db->_protect_identifiers($keys);
 			foreach ($keys as $key)
 			{
-				$sql .= ",\n\tFOREIGN KEY ($key)";
+				if (is_array($key))
+				{
+					$key = $this->db->_protect_identifiers($key);	
+				}
+				else
+				{
+					$key = array($this->db->_protect_identifiers($key));
+				}
+				
+				$sql .= ",\n\tFOREIGN KEY (" . implode(', ', $key) . ")";
 			}
 		}
-
+		
 		$sql .= "\n)";
 
 		return $sql;
diff --git a/system/database/drivers/postgre/postgre_forge.php b/system/database/drivers/postgre/postgre_forge.php
index f8dfca8..ef57834 100644
--- a/system/database/drivers/postgre/postgre_forge.php
+++ b/system/database/drivers/postgre/postgre_forge.php
@@ -134,13 +134,21 @@
 			$primary_keys = $this->db->_protect_identifiers($primary_keys);
 			$sql .= ",\n\tPRIMARY KEY (" . implode(', ', $primary_keys) . ")";
 		}
-
+		
 		if (is_array($keys) && count($keys) > 0)
 		{
-			$keys = $this->db->_protect_identifiers($keys);
 			foreach ($keys as $key)
 			{
-				$sql .= ",\n\tFOREIGN KEY ($key)";
+				if (is_array($key))
+				{
+					$key = $this->db->_protect_identifiers($key);	
+				}
+				else
+				{
+					$key = array($this->db->_protect_identifiers($key));
+				}
+				
+				$sql .= ",\n\tFOREIGN KEY (" . implode(', ', $key) . ")";
 			}
 		}
 
diff --git a/system/database/drivers/sqlite/sqlite_forge.php b/system/database/drivers/sqlite/sqlite_forge.php
index 25c74a7..a6866c8 100644
--- a/system/database/drivers/sqlite/sqlite_forge.php
+++ b/system/database/drivers/sqlite/sqlite_forge.php
@@ -144,13 +144,24 @@
 			$primary_keys = $this->db->_protect_identifiers($primary_keys);
 			$sql .= ",\n\tPRIMARY KEY (" . implode(', ', $primary_keys) . ")";
 		}
-
-		if (count($keys) > 0)
+		
+		if (is_array($keys) && count($keys) > 0)
 		{
-			$keys = $this->db->_protect_identifiers($keys);
-			$sql .= ",\n\tUNIQUE (" . implode(', ', $keys) . ")";
+			foreach ($keys as $key)
+			{
+				if (is_array($key))
+				{
+					$key = $this->db->_protect_identifiers($key);	
+				}
+				else
+				{
+					$key = array($this->db->_protect_identifiers($key));
+				}
+				
+				$sql .= ",\n\tUNIQUE (" . implode(', ', $key) . ")";
+			}
 		}
-
+		
 		$sql .= "\n)";
 
 		return $sql;
diff --git a/system/plugins/captcha_pi.php b/system/plugins/captcha_pi.php
index df95788..baa0a8d 100644
--- a/system/plugins/captcha_pi.php
+++ b/system/plugins/captcha_pi.php
@@ -92,8 +92,8 @@
 	 captcha_time int(10) unsigned NOT NULL,
 	 ip_address varchar(16) default '0' NOT NULL,
 	 word varchar(20) NOT NULL,
-	 PRIMARY KEY (captcha_id),
-	 KEY (word)
+	 PRIMARY KEY `captcha_id` (`captcha_id`),
+	 KEY `word` (`word`)
 	)