MDX - Multi-Dimensional Expressions

OLAP cubes stores data in multidimensional form whereas in the relational database data is stored in the 2 dimensions: rows and columns. OLAP cubes can store data in more than these 2 dimensions. The SQL or Structured Query Language enables us to access and manipulate the data resinding in the relational database. However SQL cannot be used for the same purposes for OLAP cubes. MDX is the language used for accessing and manipulating data in the cubes.