Ubiquitous DeviceSQL (hereinafter referred to as “DeviceSQL”) appeared in 2002 as a totally new category of data management software specialized for embedded systems and based on stream-based data management technologies. It has been used in cellular phones, onboard equipment, IP set-top boxes, communication equipment and so forth, and the latest release available as of June 2012 was DeviceSQL Release 5.1.
DeviceSQL covers all products, ranging from low-end ones to high-end ones, which cannot be covered by other embedded RDBMSs, and conforms to the Oracle PL/SQL industry-standard programming language. DeviceSQL is capable not only of making inquiries into data using an SQL statement but also of combining an SQL statement with a PL (Procedure Language) procedural language, such as an IF, FOR or LOOP statement, and thereby performing more complicated processing with a simple command.
DeviceSQL is a next-generation data management framework software (device data management) product specialized for embedded systems that offers the functionality of accessing a database (database functionality) as well as the functionality of combining an SQL statement with procedural language / import function functionality and thereby freely performing data processing (data processing functionality), such as filtering and format conversion, before and after an SQL statement.
Flexibility is at the core of DeviceSQL, with three different programming interfaces supported. Developers have their choice of a Native C API, an Intrepreted SQL API which can produce SQL queries from text strings and the DeviceSQL Language which has a syntax similar to Oracle's PL/SQL.Unique to DeviceSQL, the DeviceSQL Language is a very powerful feature of DeviceSQL. DeviceSQL Language allows developers to rapidly develop small footprint, high performance applications in a high level language. EPL is compiled into ANSI compliant C code by the DeviceSQL compiler, which is then compiled and linked directly into the target application. This allows for queries and logic to be performed natively and does not incur the overhead of query parsing that other RDBMS suffer from.
Separation of program control from table handling/data manipulation
Whereas other embedded RDBMSs support either in-memories or permanent storage media, as shown in the following figure DeviceSQL supports four data reference (store) modes: namely, streaming, in-memory, memory-mapped storage and device direct storage (paged storage) modes.
DeviceSQL allows applications to dynamically open/close a database file at any time. This functionality makes it possible to store message data on a language-by-language basis when an application requires multi-language support and easily switch, for example, from a Japanese message to an English one during the control of the application. In addition, this functionality also makes it possible to temporarily close the database file and free memory resources to make them available to other applications when there are any constraints on memory available in an embedded system and thereby enable the entire system to effectively use that memory.
Spacial Search has been added for DeviceSQL 5.0. This is made possible by the new R*-Tree index, which enables quick searches in both two (x,y) and three (x,y,z) dimensions. This exciting new feature opens up a range of possibilities for embedded applications, such as “find all the convenience stores within a 2km radius” or “display all Post Offices on my current map”.
Full text search
A Full Text Search engine supporting the N-gram algorithm has been added to DeviceSQL. The N-gram algorithm allows rapid searching of two or more tokens at a time.
FTS features include:
DeviceSQL was designed from the beginning of its development with consideration given to making the data management functionalities that are applied by embedded RDBMSs to tables also available to any data source, such as sensor outputs, data sources on a network, or the results of an operation performed by a function.
DeviceSQL can perceive input stream data as records, immediately perform a search in SQL, extract the necessary data in real time and transfer it to an application. In addition, DeviceSQL can perform a search for streaming data without change, and therefore can operate with a smaller amount of memory, without needing any redundant working memory.
DeviceSQL uses new, unprecedented, technologies to provide a framework to improve the performance, operability and intelligence of embedded systems from the aspect of data management as well as to allow embedded systems to create new added value. At the same time, it also makes it possible to achieve higher development productivity and higher quality.