improve logging for transaction feature for package gdb

.example/database/gdb/mysql/gdb_transaction.go

@@ -0,0 +1,27 @@
+package main
+
+import (
+	"github.com/gogf/gf/frame/g"
+)
+
+func main() {
+	var (
+		db    = g.DB()
+		table = "user"
+	)
+	tx, err := db.Begin()
+	if err != nil {
+		panic(err)
+	}
+	if err = tx.Begin(); err != nil {
+		panic(err)
+	}
+	_, err = tx.Model(table).Data(g.Map{"id": 1, "name": "john"}).Insert()
+	if err = tx.Rollback(); err != nil {
+		panic(err)
+	}
+	_, err = tx.Model(table).Data(g.Map{"id": 2, "name": "smith"}).Insert()
+	if err = tx.Commit(); err != nil {
+		panic(err)
+	}
+}

.example/database/gdb/mysql/gdb_transaction_closure.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"github.com/gogf/gf/database/gdb"
+	"github.com/gogf/gf/frame/g"
+)
+
+func main() {
+	var (
+		err   error
+		db    = g.DB()
+		table = "user"
+	)
+	if err = db.Transaction(func(tx *gdb.TX) error {
+		// Nested transaction 1.
+		if err = tx.Transaction(func(tx *gdb.TX) error {
+			_, err = tx.Model(table).Data(g.Map{"id": 1, "name": "john"}).Insert()
+			return err
+		}); err != nil {
+			return err
+		}
+		// Nested transaction 2, panic.
+		if err = tx.Transaction(func(tx *gdb.TX) error {
+			_, err = tx.Model(table).Data(g.Map{"id": 2, "name": "smith"}).Insert()
+			// Create a panic that can make this transaction rollback automatically.
+			panic("error")
+		}); err != nil {
+			return err
+		}
+		return nil
+	}); err != nil {
+		panic(err)
+	}
+}

.example/database/gdb/mysql/gdb_transaction_savepoint.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"github.com/gogf/gf/frame/g"
+)
+
+func main() {
+	var (
+		err   error
+		db    = g.DB()
+		table = "user"
+	)
+	tx, err := db.Begin()
+	if err != nil {
+		panic(err)
+	}
+	defer func() {
+		if err := recover(); err != nil {
+			_ = tx.Rollback()
+		}
+	}()
+	if _, err = tx.Model(table).Data(g.Map{"id": 1, "name": "john"}).Insert(); err != nil {
+		panic(err)
+	}
+	if err = tx.SavePoint("MyPoint"); err != nil {
+		panic(err)
+	}
+	if _, err = tx.Model(table).Data(g.Map{"id": 2, "name": "smith"}).Insert(); err != nil {
+		panic(err)
+	}
+	if _, err = tx.Model(table).Data(g.Map{"id": 3, "name": "green"}).Insert(); err != nil {
+		panic(err)
+	}
+	if err = tx.RollbackTo("MyPoint"); err != nil {
+		panic(err)
+	}
+	if err = tx.Commit(); err != nil {
+		panic(err)
+	}
+}