Dyalog-APL application with threads on the basis of ActiveX data objects

Abstract

This paper presents an implementation of ActiveX Data Objects (ADO) in multithreading Dyalog-APL applications providing high performance access to any data source. The suggested approach is based upon an OLEClient object of Dyalog-APL that provides an OLE (Object Linking and Embedding) automation mechanism for working with ADO as an OLE Automation Server. This concept of such Dyalog-APL applications consists in a presentation of data-processing on 3 levels of hierarchy:{ {OPERATION)ε TASK}εJOB.A synchronisation of database operations in threads is supported by ADO events. Low level operations are accumulated in a library of functions that can also be used autonomously in a single thread for solution of private tasks. These functions are optimised to work in a Dyalog-APL environment. It is available to use in a root of a objects tree RECORDSET object. Data-processing can be carried out directly at a low level to optimise performance, other objects can be created when necessary for the solution of concrete tasks. Many of the RECORDSET operations can be notified before and after each other. OLE is very dependent on the Visual Basic programming language and the syntax of APL is more restricted than the syntax of Visual Basic. It is discussed accommodation problems from syntax point of view.