Add DB.String

db.go

@@ -6,6 +6,7 @@ import (
 	"errors"
 	"fmt"
 	"reflect"
+	"strings"
 	"sync/atomic"
 
 	"github.com/uptrace/bun/dialect/feature"
@@ -60,6 +61,18 @@ func NewDB(sqldb *sql.DB, dialect schema.Dialect, opts ...DBOption) *DB {
 	return db
 }
 
+func (db *DB) String() string {
+	var b strings.Builder
+	b.WriteString("DB<dialect=")
+	b.WriteString(db.dialect.Name().String())
+	if s := db.fmter.String(); s != "" {
+		b.WriteString(" ")
+		b.WriteString(s)
+	}
+	b.WriteString(">")
+	return b.String()
+}
+
 func (db *DB) DBStats() DBStats {
 	return DBStats{
 		Queries: atomic.LoadUint64(&db.stats.Queries),

example/migrate/main.go

@@ -112,7 +112,7 @@ func newDBCommand(migrator *migrate.Migrator) *cli.Command {
 			},
 			{
 				Name:  "create_sql",
-				Usage: "create SQL migration",
+				Usage: "create up and down SQL migrations",
 				Action: func(c *cli.Context) error {
 					name := strings.Join(c.Args().Slice(), "_")
 					files, err := migrator.CreateSQLMigrations(c.Context, name)

internal/dbtest/db_test.go

@@ -42,7 +42,9 @@ func pg(tb testing.TB) *bun.DB {
 		assert.NoError(tb, sqldb.Close())
 	})
 
-	return bun.NewDB(sqldb, pgdialect.New())
+	db := bun.NewDB(sqldb, pgdialect.New())
+	require.Equal(tb, "DB<dialect=pg>", db.String())
+	return db
 }
 
 func mysql(tb testing.TB) *bun.DB {
@@ -70,7 +72,9 @@ func sqlite(tb testing.TB) *bun.DB {
 	sqldb.SetMaxIdleConns(1000)
 	sqldb.SetConnMaxLifetime(0)
 
-	return bun.NewDB(sqldb, sqlitedialect.New())
+	db := bun.NewDB(sqldb, sqlitedialect.New())
+	require.Equal(tb, "DB<dialect=sqlite>", db.String())
+	return db
 }
 
 func testEachDB(t *testing.T, f func(t *testing.T, db *bun.DB)) {

schema/formatter.go

@@ -64,7 +64,7 @@ func (f Formatter) String() string {
 	for i, arg := range f.namedArgs {
 		ss[i] = fmt.Sprintf("%s=%v", arg.name, arg.value)
 	}
-	return " " + strings.Join(ss, " ")
+	return strings.Join(ss, " ")
 }
 
 func (f Formatter) IsNop() bool {