The patent is A data mapping architecture for mapping between two or more data sources without modifying the metadata or structure of the data sources themselves. Data mapping also supports updates. The architecture also supports at least the case where data sources that are being mapped, are given, their schemas predefined, and cannot be changed.En la lista de propietarios de la patente aparece un número importante de personas vinculadas a Microsoft. La voz común es considerar que es Microsoft mismo quien avanza sobre una idea que fue ampliamente aplicada a través de muchos años por muchas empresas, que puede incluír distintos perfiles de problemas, pero que es señalada especialmente como amenaza a los diseños existentes en OR mapping (mapeo de relacional a objeto y viceversa).
Primer contacto con la noticia, una advertencia temprana de Jack Herrington en CGN-Talk, desde donde se puede leer el contenido completo de la patente aprobada, y los nombres de sus propietarios. Luego, la nota en The Server Side apuntada en el título de éste artículo, aribuyendo a Microsoft la acción, y, fundamentalmente, las consecuencias. Como en la discusión de The Server Side se dice, una patente no es definitiva, sino controversial; pero implica un avance definido hacia un objetivo restrictivo: poner una idea que en varios aspectos es de dominio público y académico, en manos de un grupo de beneficiarios de futuros reclamos de propiedad intelectual.
Aunque es temprano para atribuirle un padre, los "indicios vehementes" señalan uno, y uno acostumbrado a moverse con estos valores.
La siguiente es la introducción descriptiva del invento:
[0004] The present invention disclosed and claimed herein, in one aspect thereof, comprises a mapping format designed to support a scenario where two (or more) data sources need to map to each other, without modifying the metadata or structure of the data sources themselves. Mapping is provided, for example, between an Object space and a relational database, Object space and XML data model, an XML data model and a Relational data model, or mapping could be provided between any other possible data model to XML, relational data model, or any other data model. The mapping format supports updates, and also supports the case where both data sources being mapped are given, their schemas are predefined, and cannot be changed (i.e., read-only). An approach that was previously used to map, for example, XML data to a relational database required making changes to the XML schema definition (XSD) file in order to add annotations. The mapping format of the present invention works as if the XSD file is owned by an external entity and cannot be changed. It also allows reuse of the same XSD file, without editing, for multiple mappings to different data sources (databases, etc.).Quisiera destacar el último párrafo de la introducción:
[0005] Each data model exposes at least one of three concepts (or expressions) to mapping: structure, field, and relationship. All of these concepts can be mapped between the data models. It is possible that one data model may have only one or two of the expressions to be mapped into another data model that has three expressions. The mapping structure is the base component of the mapping schema and serves as a container for related mapping fields. A field is a data model concept that holds typed data. Relationship is the link and association between two structures in the same data model, and describes how structures in the same domain relate to each other. The relationship is established through common fields of the two structures and/or a containment/reference where a structure contains another structure. These are just examples of relationships, since other relationships can be established (e.g., siblings, functions, . . . ). The present invention allows establishing arbitrary relationships. A member of a data model can be exposed as a different mapping concept depending on the mapping context.
[0006] Semantically, mapping is equivalent to a view (and a view is actually a query) with additional metadata, including reversibility hints and additional information about the two mapped domains. When one data source is mapped to another, what is really being requested is that it is desired that the Target schema is to be a view of the Source schema. Mapping is a view represented in one data domain on top of another data domain, and defines the view transformation itself. Mapping can create complex views with structural transformations on the data, which transformations create or collapse hierarchies, move attributes from one element to another, and introduce new relationships.
[0007] Mapping relates and connects the same mappable concepts between two or more mapped models. Mapping is also directional. Thus, one domain is classified as a Source and the other is classified as a Target. The directionality of mapping is important for mapping implementation and semantics, in that, a model that is mapped as a Source has different characteristics then a model that is mapped as a Target. The Target holds the view of the source model, where the mapping is materialized using the query language of the target domain. The Source is the persistent location of the data, and mapping translates the query written in the target domain query language to the source domain query language. One difference between Source and Target is that a structure or field from the Source or Target model has some restrictions regarding the number of mappings that can apply for structures and fields. In the target domain, a structure and a field can only be mapped once, whereas in the Source domain, a structure and a field can be mapped multiple times. For example, a Customers table can be mapped to a BuyingCustomer element and a ReferringCustomer element in the Target domain. However, a local element or local class can be mapped only once. Another difference that stems for the directional attribute of mapping is that mapping allows users to operate on the mapped models through the query language of the target domain (e.g., using XQuery for mapping a Relational model to an XML model, and OPath, for mapping a Relational model to an Object model).
[0008] Another important attribute of the mapping architecture is that of being updateable. In the past, developers had to write code to propagate and synchronize changes between the domains. However, in accordance with the present invention, the mapping engine now performs these tasks. That is, when the user creates, deletes, or modifies a structure in the target domain, these changes are automatically synchronized (persisted) to the source domain by the target API and mapping engine.
[0009] In another aspect thereof, the mapping architecture is stackable where multiple stages of mappings may occur from a source to a target.
[0010] To the accomplishment of the foregoing and related ends, certain illustrative aspects of the invention are described herein in connection with the following description and the annexed drawings. These aspects are indicative, however, of but a few of the various ways in which the principles of the invention may be employed and the present invention is intended to include all such aspects and their equivalents. Other advantages and novel features of the invention may become apparent from the following detailed description of the invention when considered in conjunction with the drawings....
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