MRQL (the Map-Reduce Query Language) is an SQL-like query language for map-reduce computations. It is implemented on top of Apache's Hadoop. MRQL is powerful enough to express most common data analysis tasks over many different kinds of raw data, including hierarchical data and nested collections, such as XML data. It is more powerful than other current languages, such as Hive and Pig Latin, since it can operate on more complex data and supports more powerful query constructs, thus eliminating the need for using explicit map-reduce code.
Espresso provides an API as soon as you register your database. It introspects the database schema and populates the repository with the required metadata. Each table becomes a REST endpoint with services such as pagination, filtering, and optimistic locking out-of-the-box.
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