Extension of a Semi Structured Algebra for XML to the Procedures Linked Operators

In this paper, we treat requests in XQuery in a system of mediation "everyXML".These requests use the operators of an algebra of semi-structured data which already exists and to which. we add a procedural aspect that treats the data of type document XML A mixed approach based on relational operators and models of data under shape of graphs, using timekeepers indexed in the process of reconstruction and course of road, is retained in this paper. One of algebras adopting this approach is algebra deended by G.Gardarin and T.T.D.Ngoc called XAlgebra. This XAlgebra contains at the same time: relational operations to treat the tables of XTuples and the operations of navigation for trees XML. Idea aims to extend this XAlgebra by procedures linked operators.. A type of operator accompanied by its procedures of syntax: Xcext.. add.. by (procedures) is integrated into the functional language XQuery and transforms expression FLWR into FLXCWOR . This extension operates on the table of the XTuples and on the XOperations, extend consequently the XRelation formed by the XTuples and the associated trees. Extension becomes then a extended XOperator and is added to the existing XOperators to treat the XRelation. Syntax, semantics as well as the grammar of the FLXCWOR are studied. The treatment of requests FLXCWOR passes by a syntactic analysis, the construction of a plan of execution as well as a process of evaluation. The construction of a plan of execution passes by several stages, and in the stage of decomposition we adapt the rules of (normalization, canonization and atomisation) to the new expression FLXCWOR. The evaluation of the procedure linked operator requires the conception of a new SAX.