Question

I’m writing a sql script, and I’d like to use Management Studio to develop the query, and a C# program to run it in production.

My query contains parameters, like so;

SELECT * FROM TABLE
WHERE id = @id

I can feed in a value for @id in the C# program, and that works nicely. However, I also want to declare default values for testing in Management Studio. So I really want to write something like this pseudocode;

if not declared @id
  declare @id int
  set @id=43
end if

SELECT * FROM TABLE   
WHERE id = @id

Is there any way to check to see if a variable name has already been taken?

Answer 1

I’ve managed to make some progress by marking out the default variables in the script, like so;

/** DEFAULTS **/

declare @id int
set @id = 43

/** END DEFAULTS **/

Then preprocessing the script in my C# program, like so;

script = RemoveBlock(script, "DEFAULTS");

And implementing the function like so;

public static string RemoveBlock(string script, string blockName)
{
    if (script == null) { return null; }

    var startTag = string.Format("/** {0} **/", blockName);
    var endTag = string.Format("/** END {0} **/", blockName);

    var startTagIdx = script.IndexOf(startTag);
    if (startTagIdx == -1) { return script; }

    var endTagIdx = script.IndexOf(endTag, startTagIdx + startTag.Length);
    if (endTagIdx == -1) { return script; }

    var endOfEndTag = endTagIdx + endTag.Length;

    var beforeBlock = script.Substring(0, startTagIdx);
    var afterBlock = script.Substring(endOfEndTag);

    return beforeBlock + afterBlock;
}

So the C# program runs a version without the variables but with parameters.