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.v23.2.dll

NuGet Packages: DevExpress.DataAccess, DevExpress.Win.PivotGrid, DevExpress.Win.TreeMap

Declaration

C#

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

VB.NET

Public Function TransformColumn(
    columnName As String,
    unfold As Boolean,
    flatten As Boolean,
    alias As String
) As TransformationNodeBuilder

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
            }
        ]
    }
]

C#

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 }
};

VB.NET

Imports DevExpress.DataAccess.DataFederation
Imports DevExpress.DataAccess.Json
' ...
Dim source = New Source("Products", jsonDataSource)

Dim query = source.
    Transform().
    TransformColumn("Products", unfold:=True, flatten:=False, "CategoryProducts").
    Build("ProductsUnfolded")

Dim federation = New FederationDataSource()
federation.Queries.Add(query)

The following schema is the result of the transformation:

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