ETLBox
Row Multiplication
This article contains example code that shows the usage of the RowMultiplication component.
Generate new output rows from input
This example shows how RowMultiplication can be used to create 3 output records from one incoming record.
public class MyRow
{
public string Text { get; set; }
public char Char { get; set; }
}
public void SplittingString() {
var source = new MemorySource<MyRow>();
source.DataAsList.Add(new MyRow() { Text = "ABC" });
var multi = new RowMultiplication<MyRow>();
multi.MultiplicationFunc =
row => {
var result = new List<MyRow>();
foreach (char c in row.Text)
result.Add(new MyRow() { Char = c });
return result;
};
var dest = new MemoryDestination<MyRow>();
source.LinkTo(multi).LinkTo(dest);
Network.Execute(source);
foreach (var row in dest.Data)
Console.WriteLine($"Char:{row.Char}");
//Output
/* Char:A
Char:B
Char:C
*/
}Generating new output with different data type
This example shows how incoming data is not only used to create 3 output rows, but also to convert the input type into a different output type.
public class MyString
{
public string Text { get; set; }
}
public class MyChar
{
public char Char { get; set; }
}
public void SplittingStringDifferentTypes() {
var source = new MemorySource<MyString>();
source.DataAsList.Add(new MyString() { Text = "ABC" });
var multi = new RowMultiplication<MyString, MyChar>();
multi.MultiplicationFunc =
row => {
var result = new List<MyChar>();
foreach (char c in row.Text)
result.Add(new MyChar() { Char = c });
return result;
};
var dest = new MemoryDestination<MyChar>();
source.LinkTo<MyChar>(multi).LinkTo(dest);
Network.Execute(source);
foreach (var row in dest.Data)
Console.WriteLine($"Char:{row.Char}");
//Output
/* Char:A
Char:B
Char:C
*/
}Normalizing document data
Consider the following json document, which contains 2 invoices. The first invoice contains 3 items, the second invoice 2 items.
{
"Invoices": [
{
"Id": 1,
"CustomerName": "Peter",
"Total": 45,
"Items": [
{
"Name": "Clock",
"Price": 20
},
{
"Name": "Socks",
"Price": 10
},
{
"Name": "Shirt",
"Price": 15
}
]
},
{
"Id": 2,
"CustomerName": "Mary",
"Total": 100,
"Items": [
{
"Name": "Clock",
"Price": 29
},
{
"Name": "Dress",
"Price": 71
}
]
}
]
}If we want to extract the items and the header data for each invoice into separate entities, we can use the RowMulitplication to achieve this.
var source = new JsonSource("res/examples/invoices.json");
var invoiceHeaders = new MemoryDestination();
var invoiceLines = new MemoryDestination();
var duplicate = new Multicast();
var extractHeader = new RowTransformation();
extractHeader.TransformationFunc = (row) => {
var dict = row as IDictionary<string, object>;
dict.Remove("Items");
return row;
};
var extractLines = new RowMultiplication();
extractLines.MultiplicationFunc = (row) => {
var extractedLines = new List<ExpandoObject>();
var itemsArray = (row as dynamic).Items as List<object>;
foreach (dynamic line in itemsArray) {
line.InvoiceId = (row as dynamic).Id;
extractedLines.Add(line);
}
return extractedLines;
};
source.LinkTo(duplicate);
duplicate.LinkTo(extractHeader);
extractHeader.LinkTo(invoiceHeaders);
duplicate.LinkTo(extractLines);
extractLines.LinkTo(invoiceLines);
Network.Execute(source);
Console.WriteLine("Total invoices: " + invoiceHeaders.Data.Count);
Console.WriteLine("Total lines for all invoices: " + invoiceLines.Data.Count);
//Ouput
/*
Total invoices: 2
Total lines for all invoices: 5
*/