Data Map Automation

The data map requires to manually specify a lot of details about the mapping of the columns and the identifiers. Data map automation is about not having to specify the whole data map by hand but instead call methods to do so. The price we pay for automation is that we cannot control all aspects of the mapping. What we gain, besides convenience, is that the model and the source get decoupled more.

Category Mapping

It is possible to group parameters into categories and tables using annotations. Then there is a function to automatically turn this into a specific kind of data map call category map. Inside DataLink this is an ordinary classic data map and has a data map name. But we can add this data map using the name of the category.

dl::AddCategoryMapping(MapName, Category, Attributes)
Arguments:
  • MapName – Data map name (string)
  • Category – Category name (string)
  • Attributes – Column attribute

The category can be specified using annotations dl::Category: for the category and dl::Table: for the tables inside this category. An example is given below:

DeclarationSection Declaration_Category {
    dl::Category: Cat;            ! <----  annotation: category
    Set SI {
        Index: i;
    }
    Set SJ {
        Index: j;
    }
    Parameter p0 {
        dl::Table: Dim0Table;    ! <----  annotation: table
    }
    Parameter p1 {
        IndexDomain: i;
        dl::Table: Dim1Table;    ! <----  annotation: table
    }
    Parameter p2 {
        IndexDomain: (i,j);
        dl::Table: Dim2Table;    ! <----  annotation: table
    }
}

This creates one category with three tables. Instead of creating a data map, we can add this using only the name of the category “Cat” using:

dl::AddCategoryMapping(
    "TheDataMap",      ! The name of this data map
    "Cat",             ! The name of the category (from annotation dl::Category)
    ColAttributes      ! Column Attribute
);

This is equivalent as doing:

dl::DataTables += {'Dim0Table , Dim1Table , Dim2Table'} ;

SP_ClassicDataMap(dl::dt,dl::idn,dl::cn,dl::dn) := data {
    ! table            , identifier      , C, D   :  column name
    ( Dim0Table        , p0              , 1, 0 ) : "p0",

    ( Dim1Table        , SI              , 1, 1 ) : "i",
    ( Dim1Table        , p1              , 2, 0 ) : "p1",

    ( Dim1Table        , SI              , 1, 1 ) : "i",
    ( Dim1Table        , SJ              , 2, 2 ) : "j",
    ( Dim1Table        , p2              , 2, 0 ) : "p2",
};

dl::AddDataSourceMapping(
    "TheDataMap",              ! The name of this data map
    SP_ClassicDataMap,         ! The data map
    dl::DependEmpty,           ! not used
    dl::TableAttributesEmpty,  ! not used
    ColAttributes              ! Column Attribute
);

We see here that the names of the columns in the source are “filled in”. This means that we loose some control over how we map the identifiers to columns.

Last Updated: August, 2019