diff --git a/modules/setting/database.go b/modules/setting/database.go
index 49865a38a2840..892bb2b2e8a99 100644
--- a/modules/setting/database.go
+++ b/modules/setting/database.go
@@ -61,22 +61,12 @@ func LoadDBSetting() {
 	sec := CfgProvider.Section("database")
 	Database.Type = sec.Key("DB_TYPE").String()
 	defaultCharset := "utf8"
-	Database.UseMySQL = false
-	Database.UseSQLite3 = false
-	Database.UsePostgreSQL = false
-	Database.UseMSSQL = false
 
-	switch Database.Type {
-	case "sqlite3":
-		Database.UseSQLite3 = true
-	case "mysql":
-		Database.UseMySQL = true
+	EnsureDBType()
+	if Database.UseMySQL {
 		defaultCharset = "utf8mb4"
-	case "postgres":
-		Database.UsePostgreSQL = true
-	case "mssql":
-		Database.UseMSSQL = true
 	}
+
 	Database.Host = sec.Key("HOST").String()
 	Database.Name = sec.Key("NAME").String()
 	Database.User = sec.Key("USER").String()
@@ -109,6 +99,25 @@ func LoadDBSetting() {
 	Database.AutoMigration = sec.Key("AUTO_MIGRATION").MustBool(true)
 }
 
+// EnsureDBType ensures Database.UseXXX has been set to the right value
+func EnsureDBType() {
+	Database.UseMySQL = false
+	Database.UseSQLite3 = false
+	Database.UsePostgreSQL = false
+	Database.UseMSSQL = false
+
+	switch Database.Type {
+	case "sqlite3":
+		Database.UseSQLite3 = true
+	case "mysql":
+		Database.UseMySQL = true
+	case "postgres":
+		Database.UsePostgreSQL = true
+	case "mssql":
+		Database.UseMSSQL = true
+	}
+}
+
 // DBConnStr returns database connection string
 func DBConnStr() (string, error) {
 	var connStr string
diff --git a/routers/install/install.go b/routers/install/install.go
index a377c2950ba31..ecc7a46c5a4f7 100644
--- a/routers/install/install.go
+++ b/routers/install/install.go
@@ -273,6 +273,7 @@ func SubmitInstall(ctx *context.Context) {
 
 	// Test database setting.
 	setting.Database.Type = form.DbType
+	setting.EnsureDBType()
 	setting.Database.Host = form.DbHost
 	setting.Database.User = form.DbUser
 	setting.Database.Passwd = form.DbPasswd