您可以在Golang中使用SQLite ATTACH和DETACH吗

Question

I am using https://github.com/mattn/go-sqlite3 in a Golang application. I need to use multiple databases, and was wondering whether I can use ATTACH and DETACH in Golang (http://sqlite.org/lang_attach.html).

I don't have any code right now, because I don't know how else to tackle this problem except creating two database connections and joining data in the application:

db1, err := sql.Open("sqlite3", "./db1.db")

db2, err := sql.Open("sqlite3", "./db2.db")

// query db1 and db2
// put into map
// join data

It would be much easier if you could use:

attach database database1.db as db1;
attach database database2.db as db2;

select
  *
from
  db1.SomeTable a
    inner join 
  db2.SomeTable b on b.SomeColumn = a.SomeColumn;

Answer 1

You can attach a database, you would do it in SQL after opening the first database (omit error check for brevity):

db1, err := sql.Open("sqlite3", "./db1.db")
defer db1.Close()

s := "attach database '/path/to/db2.db' as db2;"

_, err = db.Exec(s)

s = `select *
     from db1.SomeTable a
     inner join db2.SomeTable b on b.SomeColumn = a.SomeColumn; `

results, err := db.Query(s)
defer results.Close()

//process results ...

_, err = db.Exec("detach database db2;")