Convert sqlx.DB to sql.DB in Go

Question

What's the best way to convert the type sqlx.DB (jmoiron/sqlx) to sql.DB (database/sql)?

I'm currently using the package github.com/golang-migrate/migrate and it requires an existing connection to follow sql.DB interface.


func Migrate(db *sqlx.DB) error {
    driver, err := postgres.WithInstance(db, &postgres.Config{})
    m, err := migrate.NewWithDatabaseInstance(
        "file://src/db/migrations",
        "postgres", driver)
    if err != nil {
        return err
    }

    return m.Up()
}

Update: I mixed the description and added more details. The title was correct.

phonaputer · Accepted Answer · 2020-06-17 22:08:57Z

9

You can convert an sql.DB (which is a struct, not an interface) to an sqlx.DB using sqlx's NewDb method: Code

This method requires your *sql.DB as well as the driver name as a string.

Here's an example using "mysql" for the driver:

var myDb *sql.DB

...

anSqlxDb := sqlx.NewDb(myDb, "mysql") // returns *sqlx.DB

Edit: to add the answer to the new question which was asked in the comments, it is also possible to do the reverse and get an *sql.DB from an *sqlx.DB.

The *sqlx.DB struct contains an embedded *sql.DB (Code). As an embedded struct, it can be retrieved using its type name (DB):

var mySqlxDb *sqlx.DB

...

var anSqlDb := mySqlxDb.DB

edited Jun 17, 2020 at 22:08

answered Jun 17, 2020 at 3:55

phonaputer

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4 Comments

Ivan Santos Over a year ago

How would you convert from sql to sqlx?

phonaputer Over a year ago

Convert what, specifically? The above code is how an instance of sql.Db can be converted to an instance of sqlx.DB.

Ivan Santos Over a year ago

Convert the opposite, from sqlx.DB to sql.Db

phonaputer Over a year ago

Let me add that to my answer (although it is a different question).

Eklavya · Accepted Answer · 2020-06-17 17:28:45Z

5

In doc

sqlx.DB is a wrapper around sql.DB which keeps track of the driverName upon Open, used mostly to automatically bind named queries using the right bindvars.

So you can do like

db, err := sqlx.Connect("postgres", "user=foo dbname=bar sslmode=disable")
sqlDB := db.DB // sqlDB is *sql.DB

edited Jun 17, 2020 at 17:28

answered Jun 17, 2020 at 16:09

Eklavya

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