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Programmatically Import Delimited Text File with Derived Columns into Flat File Destination Using SSIS’s Script Task Tool

This article is in response to a request that was sent by one of my blog’s subscribers regarding scripting an SSIS package with derived columns that sources text file and writes data into another text file. Thus, this article demonstrates creating a SQL Server Integration Services package that imports a text file with derived column transformation into flat file destination using a Script Task component.

We begin by launching Microsoft Visual Studio and creating a new Integration Services Project which is located under Business Intelligence Projects category.
After you have assigned a project name, proceed to click and drag the Script Task in the Control Flow pane of the package’s toolbox.
Right-click the script task and click on “Edit”
Under the Script Task Editor change the “ScriptLanguage” to “Microsoft Visual C# 2008”.
In Project Explorer, ensure the following references are added:
Back to the code window, ensure that the following namespaces are declared:
using System;
using System.Data;
using System.Data.Sql;
using System.Data.SqlTypes;
using System.Data.SqlClient;
using Microsoft.SqlServer.Server;
using Microsoft.SqlServer.Dts.Tasks;
using Microsoft.SqlServer.Dts.Runtime;
using Microsoft.SqlServer.Dts.Pipeline.Wrapper;
using RuntimeWrapper = Microsoft.SqlServer.Dts.Runtime.Wrapper;
using System.IO;
After the above declarations, proceed to create an instance of application:
Application selectSIFISO_app = new Application();
The next step is to create an SSIS package object:
Package sS_pkg = new Package();
Assign relevant package name and description:
sS_pkg.Name = “Load Flat File Source into Flat File Destination Using C#”;
sS_pkg.Description = “Programmatically create an SSIS 2008 package that loads a Flat File Source into Flat File Destination Using Script Task’s C# language”;

Insert the Data Flow Task with an appropriate name and some buffer space for processing of file (the last part is optional – you can also use default buffer allocation):
TaskHost taskHost = sS_pkg.Executables[0] as TaskHost;
MainPipe dataFlowTask = (MainPipe)taskHost.InnerObject;
taskHost.Name = “Dynamic Data Flow Task”;
taskHost.Properties[“DefaultBufferMaxRows”].SetValue(taskHost, “1000000”);

Insert the Flat File connection
ConnectionManager connectionManagerFlatFile = sS_pkg.Connections.Add(“FLATFILE”);
You can change this path depending on where you have stored the flat file
connectionManagerFlatFile.ConnectionString = @”C:\Temp\flat_src.txt”;
Assign a name to the flat file connection
connectionManagerFlatFile.Name = “TXT_FlatFile”;
Indicate that the flat file is delimited
connectionManagerFlatFile.Properties[“Format”].SetValue(connectionManagerFlatFile, “Delimited”);
Indicate whether the source file has column headings or not – in this case, our sample data has column headings.
connectionManagerFlatFile.Properties[“ColumnNamesInFirstDataRow”].SetValue(connectionManagerFlatFile, Convert.ToBoolean(true));
Get a native Flat File connection
RuntimeWrapper.IDTSConnectionManagerFlatFile100 connectionFlatFile = connectionManagerFlatFile.InnerObject as RuntimeWrapper.IDTSConnectionManagerFlatFile100;
Declare a local variable that will be used in this demonstration:
string line;
int k =0; ;

Determine the number of columns by reading the sample Flat File – line by line.
using (StreamReader file = new StreamReader(@”C:\Temp\flat_src.txt”))
while ((line = file.ReadLine()) != null)
char[] delimiters = new char[] { ‘|’ };
string[] parts = line.Split(delimiters, StringSplitOptions.RemoveEmptyEntries);
for (int i = 0; i < parts.Length;i++) { RuntimeWrapper.IDTSConnectionManagerFlatFileColumn100 flatFileCol = connectionFlatFile.Columns.Add() as RuntimeWrapper.IDTSConnectionManagerFlatFileColumn100; sS_AssignColumnProperties(flatFileCol, parts[i], “|”); } //Exit file after reading the first line break; } } catch (Exception ex) { throw ex; } finally { file.Close(); } }

Edit the last Flat File column delimiter into NewLine instead of a Comma
connectionFlatFile.Columns[connectionFlatFile.Columns.Count – 1].ColumnDelimiter = Environment.NewLine;
Insert Flat File source component
IDTSComponentMetaData100 componentSource = dataFlowTask.ComponentMetaDataCollection.New();
componentSource.Name = “FlatFileSource”;
componentSource.ComponentClassID = “DTSAdapter.FlatFileSource”;

Insert source design-time instance and initialise component
CManagedComponentWrapper instanceSource = componentSource.Instantiate();

Set source connection
componentSource.RuntimeConnectionCollection[0].ConnectionManagerID = connectionManagerFlatFile.ID;
componentSource.RuntimeConnectionCollection[0].ConnectionManager = DtsConvert.ToConnectionManager90(connectionManagerFlatFile);

Reinitialize Flat File source metadata,

Derived Column
IDTSComponentMetaData100 componentDerivedTransform = dataFlowTask.ComponentMetaDataCollection.New();
componentDerivedTransform.Name = “Derived Col Transform”;
componentDerivedTransform.ComponentClassID = “DTSTransform.DerivedColumn”;
CManagedComponentWrapper DesignDerivedTransformColumns = componentDerivedTransform.Instantiate();

design time
componentDerivedTransform.InputCollection[0].ExternalMetadataColumnCollection.IsUsed = false;
componentDerivedTransform.InputCollection[0].HasSideEffects = false;

Create the path from source to derived columns, and further insert two derived columns; the first one displays a full name while the other derived column inserts a date to record when the file/record was loaded.
IDTSPath100 SourceToDerivedPath = dataFlowTask.PathCollection.New();
SourceToDerivedPath.AttachPathAndPropagateNotifications(componentSource.OutputCollection[0], componentDerivedTransform.InputCollection[0]);
IDTSOutputColumn100 myConCatCol = componentDerivedTransform.OutputCollection[0].OutputColumnCollection.New();
myConCatCol.Name = “FullName”;
myConCatCol.SetDataTypeProperties(Microsoft.SqlServer.Dts.Runtime.Wrapper.DataType.DT_STR, 100, 0, 0, 1252);
myConCatCol.ExternalMetadataColumnID = 0;
myConCatCol.ErrorRowDisposition = DTSRowDisposition.RD_FailComponent;
myConCatCol.TruncationRowDisposition = DTSRowDisposition.RD_FailComponent;
IDTSCustomProperty100 myConCatProp = myConCatCol.CustomPropertyCollection.New();
myConCatProp.Name = “Expression”;
myConCatProp.Value = “[LastName] + \”\n\n,\” + [FirstName]\n”;
myConCatProp = myConCatCol.CustomPropertyCollection.New();
myConCatProp.Name = “FriendlyExpression”;
myConCatProp.Value = “[LastName] + \”\n\n,\” + [FirstName]\n”;
IDTSOutputColumn100 myCol = componentDerivedTransform.OutputCollection[0].OutputColumnCollection.New();
myCol.Name = “Loaddate”;
myCol.SetDataTypeProperties(Microsoft.SqlServer.Dts.Runtime.Wrapper.DataType.DT_DBTIMESTAMP, 0, 0, 0, 0);
myCol.ExternalMetadataColumnID = 0;
myCol.ErrorRowDisposition = DTSRowDisposition.RD_FailComponent;
myCol.TruncationRowDisposition = DTSRowDisposition.RD_FailComponent;
IDTSCustomProperty100 myProp = myCol.CustomPropertyCollection.New();
myProp.Name = “Expression”;
myProp.Value = “Getdate()”;
myProp = myCol.CustomPropertyCollection.New();
myProp.Name = “FriendlyExpression”;
myProp.Value = “Getdate()”;
IDTSInput100 DerivedColumnInput = componentDerivedTransform.InputCollection[0];
IDTSVirtualInput100 DerivedColumnVirtualInput = DerivedColumnInput.GetVirtualInput();
IDTSVirtualInputColumnCollection100 DerivedColumnVirtualInputColumns = DerivedColumnVirtualInput.VirtualInputColumnCollection;

Added the below to validate input columns
for each (IDTSVirtualInputColumn100 virtualInputColumnDT in DerivedColumnVirtualInputColumns)
// Select column, and retain new input column
IDTSInputColumn100 inputColumn = DesignDerivedTransformColumns.SetUsageType(DerivedColumnInput.ID, DerivedColumnVirtualInput, virtualInputColumnDT.LineageID, DTSUsageType.UT_READONLY);

Declare a new StreamWriter object and create a text file that will be used for output – provided it does not exist.

StreamWriter SW;
if (!File.Exists(“E:\\MyTextFile.txt”))
//Create output text file
SW = File.CreateText(“E:\\MyTextFile.txt”);
//Insert column row separated by pipe
//Close the file

Insert the Flat File Destination connection
ConnectionManager connectionManagerFlatFileDestionation = sS_pkg.Connections.Add(“FLATFILE”);
You can change this path depending on where you have stored the flat file
connectionManagerFlatFileDestionation.ConnectionString = “E:\\MyTextFile.txt”;
Assign a name to the flat file connection
connectionManagerFlatFileDestionation.Name = “Sample_TXT_FlatFile_Des”;
Indicate that the flat file is delimited
connectionManagerFlatFileDestionation.Properties[“Format”].SetValue(connectionManagerFlatFileDestionation, “Delimited”);
Indicate whether the source file has column headings or not – in this case, our sample data has column headings.
connectionManagerFlatFileDestionation.Properties[“ColumnNamesInFirstDataRow”].SetValue(connectionManagerFlatFileDestionation, Convert.ToBoolean(true));
Get a native Flat File connection
RuntimeWrapper.IDTSConnectionManagerFlatFile100 connectionFlatFileDestionation = connectionManagerFlatFileDestionation.InnerObject as RuntimeWrapper.IDTSConnectionManagerFlatFile100;
Determine the number of columns by reading the sample Flat File – line by line.
using (StreamReader file = new StreamReader(“E:\\MyTextFile.txt”))
while ((line = file.ReadLine()) != null)
char[] delimiters = new char[] { ‘|’ };
string[] parts = line.Split(delimiters, StringSplitOptions.RemoveEmptyEntries);
for (int j = 0; j < parts.Length; j++) { RuntimeWrapper.IDTSConnectionManagerFlatFileColumn100 flatFileCol = connectionFlatFileDestionation.Columns.Add() as RuntimeWrapper.IDTSConnectionManagerFlatFileColumn100; sS_AssignColumnProperties(flatFileCol, parts[j], “|”); k++; } //Exit file after reading the first line break; } } catch (Exception ex) { throw ex; } finally { file.Close(); } }

Edit the last Flat File column delimiter into NewLine instead of a Comma
connectionFlatFileDestionation.Columns[connectionFlatFileDestionation.Columns.Count – 1].ColumnDelimiter = Environment.NewLine;
Insert Flat File Destination component
IDTSComponentMetaData100 componentDestination = dataFlowTask.ComponentMetaDataCollection.New();
componentDestination.Name = “FlatFileDestination”;
componentDestination.ComponentClassID = “DTSAdapter.FlatFileDestination”;

Insert source design-time instance and initialize component
CManagedComponentWrapper instanceDestination = componentDestination.Instantiate();

Set source connection
componentDestination.RuntimeConnectionCollection[0].ConnectionManagerID = connectionManagerFlatFileDestionation.ID;
componentDestination.RuntimeConnectionCollection[0].ConnectionManager = DtsConvert.ToConnectionManager90(connectionManagerFlatFileDestionation);

Reinitialize Flat File source metadata,

Connect the Flat File source to the OLE DB Destination component
dataFlowTask.PathCollection.New().AttachPathAndPropagateNotifications(componentDerivedTransform.OutputCollection[0], componentDestination.InputCollection[0]);
Get input and virtual input for a destination to select and map columns
IDTSInput100 destinationInput = componentDestination.InputCollection[0];
IDTSVirtualInput100 destinationVirtualInput = destinationInput.GetVirtualInput();
IDTSVirtualInputColumnCollection100 destinationVirtualInputColumns = destinationVirtualInput.VirtualInputColumnCollection;

Declare local integer variable that will be used for looping and mapping transformed columns to destination columns

int new_i=0;
foreach (IDTSVirtualInputColumn100 virtualInputColumn in destinationVirtualInputColumns)
if (new_i < k) { // Select column, and retain new input column IDTSInputColumn100 inputColumn = instanceDestination.SetUsageType(destinationInput.ID, destinationVirtualInput, virtualInputColumn.LineageID, DTSUsageType.UT_READONLY); // Find external column by name IDTSExternalMetadataColumn100 externalColumn = destinationInput.ExternalMetadataColumnCollection[inputColumn.Name]; // Map input column to external column instanceDestination.MapInputColumn(destinationInput.ID, inputColumn.ID, externalColumn.ID); new_i++; } }

Reinitialize Derived Column Transformation component’s metadata

Execute the package or disable the below code if you intend to run+ the package later
Finally, save the package – in this case, we have opted to save the package into a file system
selectSIFISO_app.SaveToXml(@”E:\newFFArticle.dtsx”, sS_pkg, null);
Dts.TaskResult = (int)ScriptResults.Success;}

In addition to the above code, you will notice that some part of the code references the below function. This function is used to assign DTS column properties:
private static void sS_AssignColumnProperties(RuntimeWrapper.IDTSConnectionManagerFlatFileColumn100 flatFileCol, string getColName, string getDelim)

Assign delimiter:
flatFileCol.ColumnType = “Delimited”;
flatFileCol.ColumnDelimiter = getDelim;

Indicate column data type – in this case, all the source columns will be set to String Data Type:
flatFileCol.DataType = RuntimeWrapper.DataType.DT_STR;
Indicate column width – in this case, the width of all source columns will be set to a length of 100:
flatFileCol.ColumnWidth = 100;
Assign column name:
RuntimeWrapper.IDTSName100 columnName = flatFileCol as RuntimeWrapper.IDTSName100;
columnName.Name = getColName.ToString();

It’s that simple!
You can now execute your script task and the package will be created in the location you specified.
For the complete C# solution to this article, see the “Requirements” section for a file name called “selectSIFISO_Flat_File_Source_into_Derived_then_FlatFile_Destination_Using_CSharp.txt”.



October 14, 2022
Sifiso is Data Architect and Technical Lead at SELECT SIFISO – a technology consulting firm focusing on cloud migrations, data ingestion, DevOps, reporting and analytics. Sifiso has over 15 years of across private and public business sectors, helping businesses implement Microsoft, AWS and open-source technology solutions. He is the member of the Johannesburg SQL User Group and also hold a Master’s Degree in MCom IT Management from the University of Johannesburg.

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