OLE DB, Universal Data Access, COM, Rowset, Data Provider, Query Processing, Legacy Systems. 1. Introduction The proliferation of data sources in the client-server era of the mid-1990s presented a formidable challenge: each data store (relational database, email server, file system, directory service) exposed a proprietary API. Open Database Connectivity (ODBC) solved part of the problem by standardizing SQL-based relational access but explicitly excluded non-relational, non-SQL, or hierarchical data sources.

(Generated for Academic Review) Affiliation: (Conceptual Database Systems Lab) Abstract: Microsoft’s Object Linking and Embedding for Databases (OLE DB) emerged in the late 1990s as a ambitious successor to ODBC, aiming to provide universal access to both relational and non-relational data sources. Unlike its predecessor, which was constrained to SQL-based sources, OLE DB introduced a COM-based interface set designed for tabular data providers of any shape—from indexed sequential files to directory services. This paper provides a comprehensive architectural analysis of OLE DB, dissecting its core abstractions: Data Sources, Sessions, Command objects, and the critical Rowset object. We examine the dual roles of OLE DB as both a consumer interface and a provider interface, highlighting the performance implications of its cursor engine and delayed schema resolution. Furthermore, we evaluate the query processing mechanisms, particularly the interaction between consumer-side processing and provider-side indexing. Finally, we trace the decline of OLE DB in favor of ADO.NET and modern SqlClient drivers, concluding with lessons learned for contemporary polyglot data access frameworks.

OLE DB: A Retrospective Analysis of a Universal Data Access Paradigm, Its Architecture, Query Processing, and Legacy Impact