Skip to main content

8 Practical Biml Tips

Why These Tips Help​

Biml combines XML with embedded C#, which makes editing, debugging, and escaping more involved than plain XML. The following tips address the friction points that come up most often during day to day Biml work in Visual Studio.

1. Improve the Copy and Paste Experience​

The XML editor in Visual Studio reformats Biml on paste, which corrupts indentation. To stop this, open the Tools menu, select Options, expand Text Editor, expand XML, and choose Formatting. Uncheck both options under Auto Reformat. Pasted Biml then keeps its original whitespace.

2. Put Directive Tags at the Bottom of the File​

When directive tags appear before the opening 'Biml' XML tag, Visual Studio falls back to a plain text editor and loses XML formatting and IntelliSense. Moving the directives to the bottom of the file, after the closing 'Biml' tag, restores both. Directive position does not affect the generated packages.

3. Start From a Vanilla Biml File​

Before adding script, build a static Biml file that produces a package covering most of the expected functionality. Copy that working file and use it as the base when scripting begins. Mixing C# and Biml elements makes structural mistakes easier; starting from a known-good shape isolates the script issues. Test against a small dataset so each compilation produces a manageable number of packages.

4. Test and Save Often​

Use Check Biml for Errors or Generate SSIS Packages from the context menu frequently. Both actions also save the file. Biml error messages are sparse, often refer to the wrong line, and small typos can have a large effect, so frequent compilation surfaces problems while the change set is still small.

5. Escape Special XML Characters​

XML reserves five characters that need escaping or wrapping in CDATA inside element content:

  • double quote, escape as 'and quot semicolon'
  • single quote, escape as 'and apos semicolon'
  • less than, escape as 'and lt semicolon'
  • greater than, escape as 'and gt semicolon'
  • ampersand, escape as 'and amp semicolon'

For example, the following 'DirectInput' will fail because the greater than is parsed as XML:

<DirectInput>
SELECT Name FROM dbo.People WHERE Age > 25
</DirectInput>

Wrap the SQL in CDATA:

<DirectInput>
<![CDATA[SELECT Name FROM dbo.People WHERE Age > 25]]>
</DirectInput>

Or escape the operator:

<DirectInput>
SELECT Name FROM dbo.People WHERE Age &gt; 25
</DirectInput>

6. Escape Special C# Characters​

Inside C# code nuggets, the backslash and the two quote types need escaping with a leading backslash:

  • backslash, escape as two backslashes
  • single quote, escape as backslash then single quote
  • double quote, escape as backslash then double quote

A Windows file path inside a regular C# string literal:

string fileName = "C:\\Data\\Source.txt";

Or use a verbatim string to avoid escaping the backslashes:

string fileName = @"C:\Data\Source.txt";

7. Learn Some Basic C#​

C# is the principal language of the .NET framework and is used across SSIS scripts, web services, and SQL CLR procedures. A few hours spent on the basics, types, control flow, and string handling, pays back quickly when reading or writing BimlScript.

8. Learn From Samples​

Working samples are the fastest way to absorb idiomatic Biml patterns. Compile the samples, change one element at a time, and observe the effect on the generated package. Reading other people's solutions to the same problem accelerates fluency more than any reference document.

Naming Convention Bonus Tip​

Naming tasks and transformations with a consistent prefix makes it easier to trace error messages back to the source Biml. Common prefixes include EXECSQL for Execute SQL Task, ADOLOOP for ADO Foreach Loop, FILELOOP for File Foreach Loop, DFLOW for Dataflow, OLEDBSRC for OLE DB Source, DRVCOL for Derived Column, and LKP for Lookup. Snippets for common Biml structures such as if-then-else and column iteration loops save typing on repetitive scaffolding.