diff --git a/adapter.go b/adapter.go
index f61f88d..b3ed4d1 100644
--- a/adapter.go
+++ b/adapter.go
@@ -20,7 +20,6 @@ import (
 
 	"github.com/casbin/casbin/model"
 	_ "github.com/go-sql-driver/mysql" // This is for MySQL initialization.
-
 )
 
 // DBAdapter represents the database adapter for policy persistence, can load policy from database or save policy to database.
@@ -39,18 +38,26 @@ func NewDBAdapter(driverName string, dataSourceName string) *DBAdapter {
 	return &a
 }
 
-func (a *DBAdapter) open() {
+func (a *DBAdapter) createDatabase() error {
 	db, err := sql.Open(a.driverName, a.dataSourceName)
 	if err != nil {
-		panic(err)
+		return err
 	}
+	defer db.Close()
 
 	_, err = db.Exec("CREATE DATABASE IF NOT EXISTS casbin")
 	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (a *DBAdapter) open() {
+	if err := a.createDatabase(); err != nil {
 		panic(err)
 	}
 
-	db, err = sql.Open("mysql", a.dataSourceName+"casbin")
+	db, err := sql.Open(a.driverName, a.dataSourceName+"casbin")
 	if err != nil {
 		panic(err)
 	}
@@ -137,17 +144,17 @@ func (a *DBAdapter) LoadPolicy(model model.Model) {
 	}
 }
 
-func (a *DBAdapter) writeTableLine(ptype string, rule []string) {
-	line := "'" + ptype + "'"
-	for i := range rule {
-		line += ",'" + rule[i] + "'"
+func (a *DBAdapter) writeTableLine(stm *sql.Stmt, ptype string, rule []string) {
+	params := make([]interface{}, 0, 5)
+	params = append(params, ptype)
+	for _, v := range rule {
+		params = append(params, v)
 	}
-	for i := 0; i < 4-len(rule); i++ {
-		line += ",''"
+	need := 5 - len(params)
+	for i := 0; i < need; i++ {
+		params = append(params, "")
 	}
-
-	_, err := a.db.Exec("insert into policy values(" + line + ")")
-	if err != nil {
+	if _, err := stm.Exec(params...); err != nil {
 		panic(err)
 	}
 }
@@ -160,15 +167,21 @@ func (a *DBAdapter) SavePolicy(model model.Model) {
 	a.dropTable()
 	a.createTable()
 
+	stm, err := a.db.Prepare("insert into policy values(?, ?, ?, ?, ?)")
+	if err != nil {
+		panic(err)
+	}
+	defer stm.Close()
+
 	for ptype, ast := range model["p"] {
 		for _, rule := range ast.Policy {
-			a.writeTableLine(ptype, rule)
+			a.writeTableLine(stm, ptype, rule)
 		}
 	}
 
 	for ptype, ast := range model["g"] {
 		for _, rule := range ast.Policy {
-			a.writeTableLine(ptype, rule)
+			a.writeTableLine(stm, ptype, rule)
 		}
 	}
 }