在包之间共享SQL连接的惯用方式是什么？

I usually declare a public Db variable in the main package

package main

var Db *sql.DB

func main() {
    var err error
    Db, err = sql.Open("sqlite3", BARS_FILE)
    if err != nil {
        log.Fatal(err)
    }

    defer Db.Close()
    // passing Db as a parameter to other functions in other packages (database 
    // repositories) 

}

Is there a better way of doing this?

According to http://golang.org/pkg/database/sql/#DB it is safe to use sql.DB this way:

DB is a database handle. It's safe for concurrent use by multiple goroutines.

And IMHO it is ok to use it that way. Maybe later, when this variable becomes bottleneck you could create more handles. It could happen if a lot of gouroutines start using it. But do not optimize before it is necessary.