Database

CREATE TABLE IF NOT EXISTS `tbl_sample`
(
  `tbl_sample_id` INT UNSIGNED NOT NULL,
  `tracked_id` INT UNSIGNED NOT NULL,
  -- other columns goes here,
  PRIMARY KEY (`tbl_sample_id`, `tracked_id`)
)ENGINE = MyISAM

CREATE TABLE IF NOT EXISTS `tbl_sample`
(
  `tbl_sample_id` INT UNSIGNED NOT NULL,
  `tracked_id` INT UNSIGNED NOT NULL,
  -- other columns goes here,
  PRIMARY KEY (`tbl_sample_id`),
  INDEX `track` (`track_id` ASC)
)ENGINE = MyISAM

• Personally I would define any column combinations that are unique in real world as unique, natural keys, not as primary keys.
• Beyond that I would define a single columns surrogate key for all tables and always fetch/modify rows based on this surrogate key.

SqlConnection con = new SqlConnection("connection string with the user name here");
try
{
    con.Open();
}
catch (SqlException ex)
{
    //Handle exception here
}

Jörgen Andersson wrote:

catch (Exception ex)

turion87 wrote:

Another idea was XML.(also only low experience) Is it possible for me to work with SQL statements in it?

turion87 wrote:

How fast is XML? (compared to mySQL and MS Access)

turion87 wrote:

okay, now I need only a tip which kind of LOCAL database I should use.