用gorm编写鹅围棋迁移

Question

A default goose go migration prepares a function providing an *sql.Tx:

A transaction is provided, rather than the DB instance directly, since goose also needs to record the schema version within the same transaction. Each migration should run as a single transaction to ensure DB integrity, so it's good practice anyway.

I would like to write my migration using gorm migrations, but I’m not sure how to use the given transaction to that purpose. Here’s an example:

func Up_20151230135812(txn *sql.Tx) {
  txn.CreateTable(&User{})
}

The build gives me txn.CreateTable undefined (type *sql.Tx has no field or method CreateTable) as expected. How can I grab the transaction for use with gorm?

Answer 1

goose know nothing about gorm and his functions (CreateTable etc.)

Look at the end of goose / lib / goose / migration_go.go

goose just create transaction

db, err := goose.OpenDBFromDBConf(&conf)
if err != nil {
    log.Fatal("failed to open DB:", err)
}
defer db.Close()

txn, err := db.Begin()
if err != nil {
    log.Fatal("db.Begin:", err)
}

{{ .Func }}(txn)

err = goose.FinalizeMigration(&conf, txn, {{ .Direction }}, {{ .Version }})
if err != nil {
    log.Fatal("Commit() failed:", err)
}

and use sql.Tx from "database/sql" package

but you can implement custom wrapper using gorm ;-)