P-OQL: an OQL-oriented query language for Pcte

The paper presents P-OQL (Pcte-Object-Query-Language) a domain-oriented query language for Pcte. Pcte is the ECMA standard for a public tool interface (PTI) for system development environments (SDE) and includes as one of its major components a structurally object-oriented object management system (OMS). Whereas the ECMA standard is only concerned with navigational access to the object base, experience shows the need for a domain-oriented query language. P-OQL reflects the whole data model of Pcte especially designed to meet the requirements of system development environments. Special features like attributed links are integrated in a homogeneous way. The language can be used as an interactive query language for the end user, but the main objective is the embedded use in applications, i.e. software development tools, via the API. The embedded use enforces an elaborated integration into the normal (navigational) access to the Pcte-OMS. P-OQL is not designed to substitute the navigational access, but to complement it. Hence, the result of navigational access can be used as starting point of further domain-oriented access and vice versa. Furthermore P-OQL allows the access to attributes by navigational operations in a domain-oriented query. P-OQL includes a large set of operators and predicates. Nevertheless, extensions can be made with reasonable effort to meet the heterogeneous requirements in SDEs. First ideas to deal with problems caused by the distribution of the object base are presented.<
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