What is Database Ranking?

When you rank data you sort and filter it according to ranking criteria. Web Intelligence allows you to return unranked data from a database, then rank it in Web Intelligence.

A database ranking allows you to specify a ranking at the query and database level so that the data returned to Web Intelligence by the query is already ranked.

Database rankings allow you to answer questions like Return the top 3 customers based on the revenue they generated for each year? at the query level, without the need to return data that falls outside the ranking to Web Intelligence and then filter it using a Web Intelligence ranking.

Database ranking has the following advantages:

· Ranking data can be processing-intensive. By ranking at the database level you allow the server, which is typically far more powerful than the client machine, to perform this processing.

· Pre-ranking data reduces the amount of data retrieved across the network and stored in Web Intelligence.

A database ranking works by modifying the SQL that Web Intelligence generates to retrieve the query data. If your database supports ranking, Web Intelligence generates SQL to rank the data. Web Intelligence uses the SQL-99 Rank function in ranking SQL. (SQL is the query language supported by all relational databases (RDBMS), although each database has its own syntax.)

You can perform a database ranking only if your database supports it. If this is not the case, the Add a database ranking button is disabled on the Query Panel toolbar. Databases that support ranking are Oracle, DB2, Terradata and Redbrick.