Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for accessing a relational database using requests that conform to a non-structure query language syntax. In one aspect, a method includes receiving, from a client, a first access request that conforms to a NoSQL syntax for accessing a wide column store, wherein the first access request comprises a first event feature and a first attribute feature that are related to the wide column store, and the first attribute feature comprises a column family feature of the wide column store; translating the first access request into a second access request that conforms to a SQL syntax, wherein the second access request comprises a second event feature corresponding to the first event feature and a second attribute feature corresponding to the first attribute feature; and forwarding the second access request to a relational database.