الفهرس 
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Abstract
The thesis revealed that under the condition of number of channels are 10 , number of users are 10 running 25000 queries, and density is 0.1, Oracle 9i OLAP achieved better performance than SQL Server 2000 OLAP which can be enhanced to be better than Oracle 9i OLAP by restarting the OLAP Server during running the query streams.
• Experiments on OLAP tools indicated that more processing power and large amounts of memory can improve load, calculation, and query performance. The primary benefit of memory is in reducing disk I/O both paging and file access, which can improve response time and throughput.
The results of the performance analysis of different OLAP storage modes and various levels of aggregations for SQL Server 2000 showed the following:
• MOLAP provides the best performance but it requires high storage, this make it best suited for small cubes with frequent use and the necessity for rapid query response.
• ROLAP provides the slowest performance but has minimal storage requirements, this make it ideal for very large cubes that are infrequently queried, such as historical data.
• HOLAP provides useful compromise between performance and storage requirements and is generally suitable for cubes that require rapid query response for summaries based on a large amount of base data.