diff --git a/chrome/content/zotero/xpcom/db.js b/chrome/content/zotero/xpcom/db.js
index 5a1775dc9..b70a16c29 100644
--- a/chrome/content/zotero/xpcom/db.js
+++ b/chrome/content/zotero/xpcom/db.js
@@ -1244,16 +1244,17 @@ Zotero.DBConnection.prototype._debug = function (str, level) {
 
 Zotero.DBConnection.prototype._getTypedValue = function (statement, i) {
 	var type = statement.getTypeOfIndex(i);
+	// For performance, we hard-code these constants
 	switch (type) {
-		case statement.VALUE_TYPE_INTEGER:
+		case 1: //VALUE_TYPE_INTEGER
 			return statement.getInt64(i);
-		case statement.VALUE_TYPE_TEXT:
+		case 3: //VALUE_TYPE_TEXT
 			return statement.getUTF8String(i);
-		case statement.VALUE_TYPE_NULL:
+		case 0: //VALUE_TYPE_NULL
 			return null;
-		case statement.VALUE_TYPE_FLOAT:
+		case 2: //VALUE_TYPE_FLOAT
 			return statement.getDouble(i);
-		case statement.VALUE_TYPE_BLOB:
+		case 4: //VALUE_TYPE_BLOB
 			return statement.getBlob(i, {});
 	}
 }