SQL Server database project pre- and post-deployment script

Question

I've added an extra column to a table which I want to initialize using a query in the post deployment script. Unfortunately I can't seem to write a query which can be run every time so I'm looking for a way to check in the pre-deployment script if the column is available and pass an argument or variable to the post-deployment script which will then run the initialization query once.

Attempt 1: I tried setting a sqlcmd var in the pre-deployment script but the following syntax isn't allowed:

IF COL_LENGTH('dbo.Table','NewColumn') IS NULL
    :setvar PerformInitQuery 1

Attempt 2: I've also tried using a normal variable in the pre-deployment script:

DECLARE @PerformInitQuery BIT = 0
IF COL_LENGTH('dbo.Table','NewColumn') IS NULL
    SET @PerformInitQuery = 1

And accessing it in the post-deployment script:

IF @PerformInitQuery = 1
BEGIN
    :r ".\DeploymentScripts\PerformInitQuery.sql"
END

This last attempt seemed to work when publishing the project from Visual Studio but not on our build server; which uses SqlPackage.exe to publish the generated .dacpac file to the database.

Error SQL72014: .Net SqlClient Data Provider:

Msg 137, Level 15, State 2, Line 12
Must declare the scalar variable "@PerformInitQuery"

Answer 1

You could try using a temp table to hold values you wish to pass from pre to post scripts;

/*
     Pre-Deployment Script Template                         
    --------------------------------------------------------------------------------------
     This file contains SQL statements that will be executed before the build script.   
     Use SQLCMD syntax to include a file in the pre-deployment script.          
     Example:      :r .\myfile.sql                              
     Use SQLCMD syntax to reference a variable in the pre-deployment script.        
     Example:      :setvar TableName MyTable                            
                   SELECT * FROM [$(TableName)]                 
    --------------------------------------------------------------------------------------
    */

    select 'hello world' as [Col] into #temptable

picked up in post deployment script;

/*
Post-Deployment Script Template                         
--------------------------------------------------------------------------------------
 This file contains SQL statements that will be appended to the build script.       
 Use SQLCMD syntax to include a file in the post-deployment script.         
 Example:      :r .\myfile.sql                              
 Use SQLCMD syntax to reference a variable in the post-deployment script.       
 Example:      :setvar TableName MyTable                            
               SELECT * FROM [$(TableName)]                 
--------------------------------------------------------------------------------------
*/

declare @var nvarchar(200)
select @var = [Col] from #temptable

print @var

hello world

Update complete.