Migrations Helper Filegroups MSSQL

MigrationsHelper.cs

public static class MigrationsHelper
    {

        public static string CreateFilegroup(string filegroupName, byte numberOfFilegroupFiles, string sizeOfEachFile, string sizeOfFileGrown) {
            var sqlFromFileGroup = "";
            var sqlFromFilesCreated = new StringBuilder(4000);

            for( byte filesCreated = 0; filesCreated < numberOfFilegroupFiles; filesCreated++ )
            {
                sqlFromFilesCreated.Append($@"
                    ALTER DATABASE CURRENT
                        ADD FILE (
                            NAME = [' + DB_NAME() + '_{filegroupName}_{filesCreated}],
                            FILENAME = N''' + REPLACE(@DatabasePath, N'.mdf', N'_{filegroupName}_{filesCreated}.ndf') + ''',
                            SIZE = {sizeOfEachFile},
                            MAXSIZE = UNLIMITED,
                            FILEGROWTH = {sizeOfFileGrown}
                            )
                        TO FILEGROUP [{filegroupName}];
                ");
            }

            sqlFromFileGroup = $@"
                IF NOT EXISTS (SELECT * FROM sys.filegroups where name = '{filegroupName}') BEGIN
                    ALTER DATABASE CURRENT
                    ADD FILEGROUP [{filegroupName}]
                END

                IF EXISTS (SELECT * FROM sys.filegroups where name = '{filegroupName}') AND NOT EXISTS (SELECT * FROM sys.master_files where name like DB_NAME() + '_{filegroupName}%') BEGIN
                    DECLARE @DatabasePath nvarchar(max)
                    DECLARE @SQL nvarchar(max)

                    SELECT TOP 1 @DatabasePath = physical_name
                    FROM sys.master_files
                    WHERE database_id = DB_ID() AND file_id = 1 AND type_desc = N'ROWS'

                    SET @SQL = N'{sqlFromFilesCreated.ToString()}'
                    EXECUTE sp_executesql @SQL
                END
            ";

            return sqlFromFileGroup;
        }


        public static string SetFilegroupToTable(string filegroupName, string tableName, string primaryKeyName, string keyColumns = "Id")
        {
            var sqlFromSettedFilegroup = "";

            sqlFromSettedFilegroup = $@"
                IF EXISTS (SELECT * FROM sys.filegroups where name = '{filegroupName}') AND EXISTS (SELECT * FROM sys.master_files where name like DB_NAME() + '_{filegroupName}%') BEGIN
                    CREATE UNIQUE CLUSTERED INDEX [{primaryKeyName}]
                        ON [dbo].[{tableName}]({keyColumns})
                        WITH (DROP_EXISTING = ON) ON [{filegroupName}]
                END
            ";

            return sqlFromSettedFilegroup;
        }
    }