A method of data retrieval from a data repository in response to a query having either list of keywords and/or list of attribute-value pairs, the method comprising the steps of: providing an inverted index generated from the data repository, the inverted index indicating the attribute with which each term is encountered in each entity when such an attribute is available; retrieving data from the inverted index by searching said inverted index based on said attribute-value pairs or keywords; providing scores to entities. A method of forming an inverted index from a data repository and a search engine for retrieval of data from a data repository is also provided.