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V22.2

TransformationNodeBuilder.TransformColumn(String, Boolean, Boolean, String) Method

Transforms a column and specifies a new name for this column. The transformation type depends on the specified parameters.

Namespace: DevExpress.DataAccess.DataFederation

Assembly: DevExpress.DataAccess.v22.2.dll

NuGet Package: DevExpress.DataAccess

Declaration

public TransformationNodeBuilder TransformColumn(
    string columnName,
    bool unfold,
    bool flatten,
    string alias
)

Parameters

Name Type Description
columnName String

The name of a column that should be transformed.

unfold Boolean

true to unfold the column; otherwise, false.

flatten Boolean

true to flatten the column; otherwise, false.

alias String

A new column name.

Returns

Type Description
TransformationNodeBuilder

The result of the transformation query.

Example

The following example demonstrates how to unfold a data source’s Products array and specify a new name for this array:

Show JSON Data
[
    {
        "CategoryID": 1,
        "Products":
        [
            {
                "ProductName": "Chai",
                "UnitPrice": 18
            },
            {
                "ProductName": "Chang",
                "UnitPrice": 19
            }
        ]
    },
    {
        "CategoryID": 2,
        "Products":
        [
            {
                "ProductName": "Ikura",
                "UnitPrice": 31
            },
            {
                "ProductName": "Konbu",
                "UnitPrice": 6
            }
        ]
    }
]
using DevExpress.DataAccess.DataFederation;
using DevExpress.DataAccess.Json;
// ...
var source = new Source("Products", jsonDataSource);

var query = source
    .Transform()
    .TransformColumn("Products", unfold: true, flatten: false, "CategoryProducts")
    .Build("ProductsUnfolded");

var federation = new FederationDataSource() {
    Queries = { query }
};

The following schema is the result of the transformation:

"CategoryID:" int
"CategoryProducts"
    "ProductName": string
    "UnitPrice": int
See Also