I am trying to create some script variables in T-SQL as follows:

    /*
    Deployment script for MesProduction_Preloaded_KLM_MesSap
    */

    GO
    SET ANSI_NULLS, ANSI_PADDING, ANSI_WARNINGS, ARITHABORT, CONCAT_NULL_YIELDS_NULL, QUOTED_IDENTIFIER ON;

    SET NUMERIC_ROUNDABORT OFF;


    GO
    :setvar DatabaseName "MesProduction_Preloaded_KLM_MesSap"

However, when I run this, I get an error stating 'Incorrect syntax near ':'. What am I doing wrong?