//OpenConnection opens a connection to a MySQL database by `connStr`
// or returns error. If `connStr` is empty, error is returned.
//
// Parameters:
// - `connStr`: the URL of the database to connect to
// - `interpolateParams` : should we interpolate parameters?
//
// Returns:
// - pointer to the database connection
// - any errors that happened during this process
func OpenConnection(connStr string, interpolateParams bool) (*sql.DB, *errors.ErrorSt) {
    if connStr == "" {
        return nil, errors.Database().ReplaceMessage("No database connection string.")
    }
    connStr = connStr + "?parseTime=true&multiStatements=true"
    if interpolateParams {
        connStr += "&interpolateParams=true"
    }

    db, err := sql.Open("mysql", connStr)
    if err != nil {
        return nil, errors.Database().AddDetails(err.Error(), connStr)
    }
    return db, nil
}