OLAP

OLAP interview questions and answers

<<Previous  Next>>   OLAP database objects The following are the OLAP database objects: Cubes: Data in cubes are persisted in a summarized version that helps to analyze data quickly. The data is persisted, through which reporting can be done easily.................. Read answer Cubes A data cube stores data in a summarized version which helps in a faster analysis of data. The data is stored in such a way that it allows reporting easily................ Read answer Data Sources Data source is where the data comes from in data warehousing. The data collected from various sources and is cleaned.............. Read answer Fact Tables Data in a warehouse comes from the transactions. Fact table in a data warehouse consists of facts and/or measures. The nature of data in a fact table is usually numerical. e.g. If I want to know the number.............. Read answer Database roles Database level roles are used to manage the security of the database. The role can be either fixed or flexible............... Read answer Explain the concepts and capabilities of OLAP. Online analytical processing performs analysis of business data and provides the ability to perform complex calculations on usually low volumes of data. OLAP helps the user gain an insight on the data.............. Read answer Explain the functionality of OLAP. Multidimensional analysis:- OLAP helps the user gain an insight on the data coming from different sources. OLAP helps faster execution of complex analytical and ad-hoc queries............... Read answer What are MOLAP and ROLAP? Multidimensional Online Analytical Processing and Relational Online Analytical Processing are tools used in analysis of data which is multidimensional.................. Read answer Explain the role of bitmap indexes to solve aggregation problems. Bitmap indexes are useful in connecting smaller databases to larger databases. Bit map indexes can be very useful in performing repetitive indexes.............. Read answer Explain the encoding technique used in bitmaps indexes. For each distinct value, one bitmap is used. The number of bitmaps can be reduced using log(C) bitmaps with to represent the values in each bin................ Read answer What is Binning? Binning can be used to hold multiple values in one bin. Bitmaps are then used to represent the values in............. Read answer What is candidate check? Binning process when creates the binned indexes, answers only some queries. The base data is not checked. The process of checking the base data is called as a candidate check. Candidate check at times............. Read answer What is Hybrid OLAP?  In a Hybrid OLAP, the database gets divided into relational and specialized storage. Specialized data storage is for data with fewer details while relational storage can be used for large amount of data.............. Read answer Explain the shared features of OLAP. OLAP product by default is read only. If multiple access rights are required, admin needs to make necessary changes.................. Read answer Compare Data Warehouse database and OLTP database. Data Warehouse is used for business measures cannot be used to cater real time business needs of the organization and is optimized for lot of data, unpredictable queries. On the other hand, OLTP database is for................. Read answer What is the difference between ETL tool and OLAP tool? ETL is the process of Extracting, loading and transforming data into meaningful form. This data can be used by the OLAP tool for to visualize data in different forms. ETL tools also perform some cleaning of data.................. Read answer What is the difference between OLAP and DSS? Data driven Decision support system is used to access and manipulate data. Data Driven DSS in conjunction with On line Analytical Processing............ Read answer <<Previous  Next>>