Custom Components Development in SSIS

 SQL Server Integration Services (SSIS) allows developers to extend its built-in functionality by creating custom components. These components can be used in Data Flow Tasks to handle specialized transformations, sources, or destinations that aren't covered by the standard SSIS toolbox.

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1. Types of Custom Components in SSIS

SSIS supports three main types of custom components:

Component Type	Description
Custom Source	Reads data from non-standard sources (e.g., NoSQL databases, custom APIs).
Custom Transformation	Performs specialized data manipulations (e.g., custom parsing, encryption).
Custom Destination	Writes data to non-standard targets (e.g., custom file formats, cloud storage).

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2. How to Develop Custom SSIS Components

Custom components are typically developed in C# (or VB.NET) using the SQL Server Data Tools (SSDT) or Visual Studio.

Prerequisites

• Microsoft SQL Server Integration Services installed.

• Visual Studio (with SSDT for SQL Server).

• .NET Framework (SSIS 2019+ supports .NET Core in some cases).

• IDTSComponentMetaData100 and Microsoft.SqlServer.Dts.Pipeline namespaces.

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3. Steps to Create a Custom SSIS Component

Step 1: Create a Class Library Project

1. Open Visual Studio.

2. Create a Class Library (.NET Framework) project.

3. Add references to:

   • Microsoft.SqlServer.DTSPipelineWrap

   • Microsoft.SqlServer.DTSRuntimeWrap

   • Microsoft.SqlServer.PipelineHost

   • Microsoft.SqlServer.ManagedDTS

Step 2: Implement the Component

• Inherit from:

  • PipelineComponent (for transformations)

  • SourceComponent (for sources)

  • DestinationComponent (for destinations)

Key Methods to Override

Method	Purpose
ProvideComponentProperties()	Defines input/output columns and properties.
PreExecute()	Runs before processing rows (initialization).
ProcessInput() / ProcessOutput()	Handles data row processing.
PostExecute()	Runs after processing (cleanup).

Step 3: Register the Component

1. Sign the assembly (strongly recommended).

2. Install to GAC (gacutil /i YourComponent.dll).

3. Copy to SSIS Pipeline Components folder (C:\Program Files\Microsoft SQL Server\<version>\DTS\PipelineComponents).

Step 4: Use in SSIS

1. Open SSDT.

2. In the Data Flow Task, right-click the toolbox → Choose Items → Browse and select your custom component.

3. Drag and drop it into the Data Flow.

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4. Example: Custom Transformation Component

csharp

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using Microsoft.SqlServer.Dts.Pipeline;
using Microsoft.SqlServer.Dts.Pipeline.Wrapper;
using Microsoft.SqlServer.Dts.Runtime.Wrapper;

[DtsPipelineComponent(
    DisplayName = "Custom Uppercase Transform",
    Description = "Converts string columns to uppercase",
    ComponentType = ComponentType.Transform
)]
public class CustomUppercaseTransform : PipelineComponent
{
    public override void ProvideComponentProperties()
    {
        base.ProvideComponentProperties();
        ComponentMetaData.Name = "Custom Uppercase Transform";
        ComponentMetaData.Description = "Converts strings to uppercase";
    }

    public override void ProcessInput(int inputID, PipelineBuffer buffer)
    {
        while (buffer.NextRow())
        {
            for (int col = 0; col < buffer.ColumnCount; col++)
            {
                if (buffer.IsNull(col)) continue;
                if (buffer.GetColumnInfo(col).DataType == DataType.DT_STR ||
                    buffer.GetColumnInfo(col).DataType == DataType.DT_WSTR)
                {
                    string value = buffer.GetString(col);
                    buffer.SetString(col, value.ToUpper());
                }
            }
        }
    }
}

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5. Best Practices for Custom SSIS Components

✔ Use SSIS Buffer Efficiently – Minimize memory usage.
✔ Handle Errors Gracefully – Implement IDTSComponentMetaData100 error outputs.
✔ Optimize Performance – Avoid excessive row-by-row processing.
✔ Test Thoroughly – Validate with large datasets.
✔ Document Your Component – Provide usage instructions.

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6. When to Use Custom Components?

✅ Specialized Data Sources (e.g., MongoDB, REST APIs).
✅ Complex Business Logic (e.g., custom encryption, data masking).
✅ Performance-Critical Operations (optimized beyond Script Component).
✅ Reusable Logic (used across multiple packages).

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Conclusion

• Custom SSIS components extend SSIS beyond its built-in capabilities.

• They are written in C#/VB.NET and integrated into the Data Flow.

• Useful for specialized ETL scenarios where standard components fall short.

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