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With Entity Framework 6 and a working PostgreSQL database plus connection I am trying to run the Add-Migration and Update-Database commands and create an update script via a console app. It is possible to run the commands from a console since it are "just thin wrapper around an API", see this SO-answer for the example I used.

The creation of migrations work, three regular files are created, namely:

Initial.cs
Initial.Designer.cs
Initial.resx

Here's the console app that does not work for Update-Database.

public static void Main()
{

    // Specify the name of the database migration
    // Note: make sure to create a new name for each new migration and prefix with
    const string MIGRATION_NAME = "Initial";

    // END USER INPUT


    // Get executing path from which the location of the Update_Scripts and new 
    // Migrations can be determined.
    var executingPath = AppDomain.CurrentDomain.BaseDirectory; 



    // Write to database (PowerShell: Update-Database)
    var config = new Configuration();
    var migrator = new DbMigrator(config);
    migrator.Update(); // <= HERE IT CRASHES!

    // Now create the PostgreSQL update script.
    var scriptor = new MigratorScriptingDecorator (migrator);
    string script = scriptor.ScriptUpdate (sourceMigration: null, targetMigration: null);

    var updateScriptPath = Regex.Replace (executingPath, "Zk.Migrations/.*", 
                        "Zk/App_Data/Update_Scripts");
    File.WriteAllText (updateScriptPath + MIGRATION_NAME + ".postgresql", script);
    Console.WriteLine ("Update script {0} written to App_Data/Update_Scripts folder", MIGRATION_NAME);
}

Here the Configuration class looks as follows:

public class Configuration : DbMigrationsConfiguration<ZkContext>
{
    public Configuration ()
    {
        AutomaticMigrationsEnabled = false;
        SetSqlGenerator("Npgsql", new PostgreSqlMigrationSqlGenerator());
    }

}

Where PostgreSqlMigrationSqlGenerator class comes from this GitHub repository.

When I try to run the Update-Database part above the console app crashes on migrator.Update();. This is the exception:

Could not find any resources appropriate for the specified culture or the neutral culture. Make sure "Zk.Migrations.Initial.resources" was correctly embedded or linked into assembly "Zk.Migrations" at compile time, or that all the satellite assemblies required are loadable and fully signed.

And here's the stack trace:

System.Data.Entity.Migrations.DbMigrator.EnsureDatabaseExists (mustSucceedToKeepDatabase=
{System.Action}) in System.Data.Entity.Migrations.Infrastructure.MigratorBase.EnsureDatabaseExists
(mustSucceedToKeepDatabase={System.Action}) in
System.Data.Entity.Migrations.DbMigrator.Update (targetMigration=(null)) in
System.Data.Entity.Migrations.Infrastructure.MigratorBase.Update () in
Zk.Migrations.MigrationsTool.Main () in /home/erwin/zaaikalender/Zk.Migrations
/MigrationsTool.cs:78

I don't know how to provide the right resources and get the script to work. Should I run Enable-Migrations first and if so how? I hope someone can help me out! Thanks.

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user2609980
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1 Answers1

1

Two things that need to be done to get the console app working to add a code-first migrations, create a script and update the database:

  1. Give the .cs., .resx and .Designer.cs files that are created when adding a migration the same name as the migration scaffolding name without the migration's MigrationId preprended. Otherwise the files could not be found.
  2. Right click on the resources .resx file and chose BuildAction "EmbeddedResource", otherwise the resources cannot be found.

Full working script of the console app (which uses the PostgreSqlMigrationSqlGenerator):

/// <summary>
///     Class used to generate the code migrations and SQL script based on the Models and update the database.
///     (I.e., runs PowerShell's Add-Migration and Update-Database, and creates a PostgreSQL script.)
///     See: http://stackoverflow.com/questions/20374783/enable-entity-framework-migrations-in-mono#20382226
/// 
///     Usage: run by setting Zk.Migrations as Startup project and pressing play.
/// 
///     Classes of namespace EntityFramework.PostgreSql obtained from:
///     https://github.com/darionato/PostgreSqlMigrationSqlGenerator. License is included.
/// </summary>
class MigrationsTool
{
    /// <summary>
    ///     The entry point of the program, where the program control starts and ends.
    /// </summary>
    public static void Main()
    {
        // USER INPUT /////////////////////////////////////////////////////////////////////////////////

        // Always first create a new database migration with DatabaseStep.ADD_MIGRATION,
        // and include the created files in the project and set resource file to EmbeddedResource. 
        // After creating a migration run UPDATE_DATABASE to update the database.

        const DatabaseStep step = DatabaseStep.UPDATE_DATABASE;

        // Specify the name of the database migration in case of ADD-MIGRATION.
        // Note: Make sure to create a new name for each new migration.
        //       After creating migration include the files in the folder by right clicking on 
        //       Zk.Migrations and selecting "Add files from folder". Then add the .cs, .resx and
        //       .Designer.cs files with the name specified below.
        //       Last but not least set the .resx file's build action to EmbeddedResource by right
        //       clicking on it.
        // Make sure that the Setup.postgresql script has run manually to create the database user.

        const string MIGRATION_NAME = "CalendarAndUser";

        // END USER INPUT /////////////////////////////////////////////////////////////////////////////


        // Get executing path from which the location of the Update_Scripts and new Migrations can be determined.
        var executingPath = AppDomain.CurrentDomain.BaseDirectory; 

        // Add a new migration (PowerShell: Add-Migration)
        if (step == DatabaseStep.ADD_MIGRATION) {

            // Initialize the wrapper classes around the Entity Framework PowerShell API.
            var config = new Configuration();
            var scaffolder = new MigrationScaffolder(config); 
            var migration = scaffolder.Scaffold(MIGRATION_NAME);

            // Place migration code in main project "Migrations" folder and migration scripts in "App_Data"
            var migrationsPath = Regex.Replace(executingPath, "bin/.*", "");

            // Write migrations
            File.WriteAllText (migrationsPath + MIGRATION_NAME + ".cs", migration.UserCode);
            File.WriteAllText (migrationsPath + MIGRATION_NAME + ".Designer.cs", migration.DesignerCode);

            using (var writer = new ResXResourceWriter (migrationsPath + MIGRATION_NAME + ".resx")) 
            {
                foreach (var resource in migration.Resources) 
                {
                    writer.AddResource(resource.Key, resource.Value);
                }
            }
            Console.WriteLine("EF code migration {0} written to Migrations folder...\n\n" +
                "Next step is to include the .cs, .resx and .Designer.cs file in the project" + 
                "by right clicking on the project and selecting " +  
                "\"Add files from folder.\"\n" +
                "Then right click on {0}.resx and set build action to \"EmbeddedResource\""
                , migration.MigrationId);
        }

        else if (step == DatabaseStep.CREATE_SCRIPT)
        {
            var config = new Configuration();
            var migrator = new DbMigrator(config);
            var scriptor = new MigratorScriptingDecorator(migrator);

            // Determine name of the previous run migration if exists.
            string lastMigration = migrator.GetDatabaseMigrations().LastOrDefault();

            // Get the script 
            string script = scriptor.ScriptUpdate(sourceMigration: lastMigration, targetMigration: MIGRATION_NAME);

            // Create the PostgreSQL update script based on last migration on database and 
            // current migration.
            string formattedScript = string.Format
                ("/* * * * * * * * * * * * * * * * * * * * * * *\n" +
                " *\n" +
                " * Migration:\t\t{0}\n *\n" +
                " * Date and time:\t{1}\n" +
                " *\n" +
                " * * * * * * * * * * * * * * * * * * * * * * */\n\n" +
                "{2}", 
                MIGRATION_NAME, 
                DateTime.Now,
                script);

            // Write string to file in Migrations folder of main project
            var updateScriptPath = Regex.Replace(executingPath, "Zk.Migrations/.*", "Zk/App_Data/Migrations/");
            File.WriteAllText(updateScriptPath + MIGRATION_NAME + ".postgresql", formattedScript);
            Console.WriteLine("Update script {0}.postgresql written to Zk/App_Data/Migrations folder.\n" +
                "Please include the script by right clicking on the folder and selecting " + 
                "\"Add files to folder\"," +
                "\nIt is recommended to prefix the filename with the current datetime.", 
                MIGRATION_NAME);
        }

        // If a new migration is created the database can be updated. (PowerShell: Update-Database)
        else if (step == DatabaseStep.UPDATE_DATABASE)
        {
            var config = new Configuration();
            var migrator = new DbMigrator(config);

            // Write to database
            migrator.Update();

            // Show which migrations were applied.
            var migrationNames = string.Join(", ", migrator.GetDatabaseMigrations().ToArray().First());
            Console.WriteLine("Applied migration {0} to database.", migrationNames);
        }
    }

    /// <summary>
    ///     Enumeration for specifying the step in the migration.
    /// </summary>
    private enum DatabaseStep 
    {
        ADD_MIGRATION,
        CREATE_SCRIPT,
        UPDATE_DATABASE
    }

}
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