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WP Item 6. Expressions and Calculations . Goals of the WP item (1). Adopt a Language for Calculations and Validations, as envisaged in the package n.13 of SDMX Information Model
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WP Item 6 Expressions and Calculations SDMX Technical Working Group Paris
Goals of the WP item (1) Adopt a Language for Calculations and Validations, as envisaged in the package n.13 of SDMX Information Model The SDMX package n. 13 – Transformations and Expressions – is a generic model aimed to track the derivation of data, derived from the CWM (Common Warehouse Metamodel), a OMG standard (Object Management Group) widely used in the IT field SDMX Technical Working Group Paris
Goals of the WP item (2) Make it possible to define and exchange the algorithms either used or specified for calculating dataand the coherence rules, either enforced or looked-for between different data Design the language for defining expressions (expression language) – that is the list of the operators available and their formal grammar Design the IT formats (messages) for exchanging the definitions of the Transformations (calculations and validations defined by means of expressions)
SDMX IM – Package 13 SDMX Technical Working Group Paris
Operand: C Operator: ** b Operand: 2 p Operator: * f Result: E f Operand: M Operator nodes Reference nodes 0..* Constant node Expression nodes Transformations; internal view Einstein equation E = MC2 E = M*(C**2) SDMX Technical Working Group Paris 5
Operand: C Operand: 2 Operand: M Transformations: User view Einstein equation E = MC2 E = M*(C**2) Expression: E = M*(C**2) Result: E SDMX Technical Working Group Paris 6
Notes on Transformations • The Operands may be: • Artefacts of the model (e.g. Statistical Data) • Constants • Operator nodes • The property of “Closure” • The result is an artefact of the model (e.g. Statistical Data) • The result may be operand of other calculations SDMX Technical Working Group Paris 7
Graph of the calculations Economic research models External Institutions T53 T51 C51 C53 C3 T1 C1 T2 C4 C54 T54 C52 T52 C2 T3 C5 Statistical bulletin T60 Banks & OFI’s reports C60 T61 C61 C10 C17 T14 C15 T12 C12 Statistical products C13 C16 T13 T70 C70 C72 T72 T71 C71 C.C.R. C21 C23 T21 Supervision models C41 C22 T41 C24 T22 C42 T42 SDMX Technical Working Group Paris 8
Validation as a Calculation Formal (Structural) assurance that the formal structure of the data observations matches the Data Structure Definition, in term of concepts, their roles and their admissible values; the formal validation is not a calculation and is not defined through an expression; Of the Information Content (Plausibility) Assurance that the data content gives right information about the real world (as much as possible); to this end, it is possible to use the a-priori information about the real world and the possible redundancies of the data (e.g. the integrity rules, coherence rules, plausibility rules); this kind of validation rules is normally performed through calculations, SDMX Technical Working Group Paris
Validations as calculations • Use of the same language of the calculations • Validations possible in any phase of the process • Results of the Validations like any other data • are defined and stored • can be inquired and disseminated • can be further processed SDMX Technical Working Group Paris 10
Main goals fot the TWG meeting Share information on the existing languages (input from the Secretariat: not reinvent the wheel and start from existing experiences) : • Presentation of ESS VIPV project • Presentation of XBRL formula • Presentation of Banca d’Italia EXL Share the general principles and requisites of the solution Share the working programme for this item, involving the SWG SDMX Technical Working Group Paris
WP Item 6 Expressions and Calculations SDMX Technical Working Group Paris