Storing multidimensional data in databases is an important topic both in the industrial and scientific database communities. Arrays are offered as a multidimensional data structure by most programming languages. Conventional database systems, however, do not support arrays of arbitrary dimensionality and base type. RasDaMan is a DBMS integrating arrays as a first class data type offering both a declarative query language and a specialised storage structure for arrays. The work presented evaluates the performance of queries on multidimensional array data stored in RasDaMan versus storage in a conventional RDBMS. In the relational system, the data is both mapped to relations and stored directly as binary data in BLOBs. The queries executed were modelled after queries common in scientific applications and decision support.

RasDaMan is a universal — i.e., domain-independent — array DBMS for multidimensional arrays of arbitrary size and structure. A declarative, SQL-based array query language offers flexible retrieval and manipulation. Efficient server-based query evaluation is enabled by an intelligent optimizer and a streamlined storage architecture based on flexible array tiling and compression.

In the RasDaMan project a database system for management of multidimensional arrays is being built. It offers a declarative query language extending SQL-92 with operations on arrays of arbitrary base types and a C++ programming interface. Integrating arrays in the query language enables the system to process complex queries on high-volume multidimensional data in the database server close to physical data storage. Storage of arrays is done in tiles of arbitrary size. Operations on arrays are transformed into operations on tiles during query optimization and execution. These operations are then executed on tiles loaded from mass storage. This paper describes the underlying formal model for tile based operations on multidimensional arrays and its efficient implementation in C++ as part of the RasDaMan system.