Wikipedia
c-treeACE is a cross-platform database engine developed by FairCom Corporation. Software developers typically embed the c-treeACE engine within the applications that they create and then deploy the application and engine together as an integrated solution.
At its core, c-treeACE uses a record-oriented, Indexed Sequential Access Method ( ISAM) structure offering high speed indexing mechanisms over those files. Developers can use these direct access methods to design the data and index structures that closely parallel the needs of their application. This paradigm is sometimes referred to as an application-specific database or an embedded database because of the tightly coupled nature of the application and database.
The nature of c-treeACE allows it to be used in a range of products including: embedded systems that require limited disk and memory footprint and silent operation; shrink-wrap products developed by ISVs that require cross-platform support, minimal maintenance, and mass deployment; and enterprise systems that depend on performance and more precision control of database operations than a traditional enterprise database offers.
Two versions of the product are available. c-treeACE Express is freely available for development from FairCom's web site and supports only the client/server architecture. The client-side libraries are precompiled, making it easy to use for evaluation. c-treeACE Professional is licensed separately and supports all architectures and includes full source code for the client libraries and much of the source code for the server.
c-treeACE is one of few databases that specialize in making data locked into legacy database architecture available to modern APIs while minimizing time, resources and risks involved in modernization projects.
c-treeACE combines the benefits of NoSQL such as high performance, low latency and precise data access control, with the flexbility of SQL interfaces.