Abstract: A data warehouse is a collection of data for supporting of decision making process. Data cubes and on-line analytical processing (OLAP) have become very popular techniques to help users analyze data in a warehouse. Even though previous studies on a data warehouse and data cube have been proposed and developed, as new applications emerging, there are still technical challenges which have not been addressed well. We propose effective and efficient solutions to the challenging problems in the areas of (1) mining iceberg cube from multiple tables, (2) online answering ad-hoc aggregate queries on data streams, and (3) warehousing pattern-based clusters. Firstly, we argue that the materialized base table assumption in most of the previous studies on computing iceberg cubes is often infeasible in practice. Instead, a data warehouse is often organized with multiple tables in schemas such as star schema, snowflake schema, and constellation schema. We propose a novel approach to compute an iceberg cube from multiple tables in a data warehouse in order to avoid costly materialization of a base table. Secondly, it is infeasible to compute a full data cube for answering ad-hoc aggregate queries on data streams due to a rapid data input and the huge size of data. We develop a new method to answer online ad-hoc aggregate queries on data streams, which is to maintain and index a small subset of aggregate cells on a designed data structure. Last, we extend the data warehousing and OLAP techniques to tackle pattern-based clusters. We propose an efficient method to construct a data warehouse of non-redundant pattern-based clusters.