What's a ROLAP Tool?


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  Step 1:  The Concept

Open a Report
ROLAP stands for Relational On-line Analytical Processing. It is a type of reporting tool that provides users with the capability to do efficient "drill" or "trend" analysis on large volumes of atomic or summarized data stored in a relational database.
  Step 2:  Drill Analysis

Data may have a hierarchical relationship such as year, month, and day. ROLAP tools provide users the ability to analyze FACT variations at different levels of hierarchy. There are different types of drill analysis such as drill-down (using lower level attribute), drill-up (using higher level attribute), drill-within (using attribute from same dimension not in main hierarchy), drill-anywhere (using attributes from any dimension), and drill-across (using attributes from other dimensions).
  Step 3:  Trend Analysis

Data warehouses or data mart(s) contain historical data. ROLAP tools provide users the ability to analyze FACT trends for different business perspectives (dimensions), having different levels of hierarchy, over a given time duration.
  Step 4:  Rotation Analysis

Open a Report
ROLAP tools may present data in simple tabular reports (along X-axis and Y-axis) such as year 2000 sales (in dollars) (intersection of X-axis and Y-axis) of sales person(s) (listed along Y-axis) for 12 months (listed along X-axis). ROLAP tools provide users the ability to perform rotation analysis (referred as slicing and dicing) of tabular data by interchanging data between X-axis and Y-axis such as year 2000 sales (in dollars) of sales person(s) (listed along X-axis) for 12 months (listed along Y-axis).
  Step 5:  Data Storage

Irrespective of the data model, whether multi-dimensional or relational, ROLAP tools may be used in analyzing data stored as columns and tables in a relational database. Data may be stored in denormalized or normalized dimensions and normalized FACT(s) tables. Storage requirements are optimal for storing atomic and summarized data in a relational database when compared with a multi-dimensional database. ROLAP tools provide the capability to summarize or aggregate atomic data without having to store it.
  Step 6:  Data Access

SQL is the industry standard access language for relational databases. Data may be stored in atomic or summarized format. A SQL query will take a longer to time to read atomic data, summarize (or aggregate) it, and present it to users in a particular format when compared to a SQL query that reads summarized data, and presents it to users in a particular format. Hence, query performance is unpredictable using a ROLAP tool. Also, it is not necessary to store aggregated data in a relational database.