diff --git a/plugins/services/credential_tester.go b/plugins/services/credential_tester.go
index b557420..aa302b6 100644
--- a/plugins/services/credential_tester.go
+++ b/plugins/services/credential_tester.go
@@ -2,6 +2,7 @@ package services
 
 import (
 	"context"
+	"database/sql"
 	"fmt"
 	"io"
 	"sync"
@@ -369,3 +370,17 @@ func matchIgnoreCase(a, b string) bool {
 	}
 	return true
 }
+
+// =============================================================================
+// 通用数据库连接包装
+// =============================================================================
+
+// SQLDBWrapper 包装 sql.DB 以实现 io.Closer
+// 用于 MySQL、PostgreSQL、MSSQL、Oracle 等数据库插件的连接返回
+type SQLDBWrapper struct {
+	*sql.DB
+}
+
+func (w *SQLDBWrapper) Close() error {
+	return w.DB.Close()
+}
diff --git a/plugins/services/mssql.go b/plugins/services/mssql.go
index a1d6b48..0cb533c 100644
--- a/plugins/services/mssql.go
+++ b/plugins/services/mssql.go
@@ -98,21 +98,12 @@ func (p *MSSQLPlugin) doMSSQLAuth(ctx context.Context, info *common.HostInfo, cr
 
 	return &AuthResult{
 		Success:   true,
-		Conn:      &mssqlDBWrapper{db},
+		Conn:      &SQLDBWrapper{db},
 		ErrorType: ErrorTypeUnknown,
 		Error:     nil,
 	}
 }
 
-// mssqlDBWrapper 包装 sql.DB 以实现 io.Closer
-type mssqlDBWrapper struct {
-	*sql.DB
-}
-
-func (w *mssqlDBWrapper) Close() error {
-	return w.DB.Close()
-}
-
 // classifyMSSQLErrorType MSSQL错误分类
 func classifyMSSQLErrorType(err error) ErrorType {
 	if err == nil {
diff --git a/plugins/services/mysql.go b/plugins/services/mysql.go
index 4db1463..543f3a2 100644
--- a/plugins/services/mysql.go
+++ b/plugins/services/mysql.go
@@ -104,24 +104,14 @@ func (p *MySQLPlugin) doMySQLAuth(ctx context.Context, info *common.HostInfo, cr
 
 	state.IncrementTCPSuccessPacketCount()
 
-	// MySQL 使用 sql.DB，包装为 io.Closer
 	return &AuthResult{
 		Success:   true,
-		Conn:      &sqlDBWrapper{db},
+		Conn:      &SQLDBWrapper{db},
 		ErrorType: ErrorTypeUnknown,
 		Error:     nil,
 	}
 }
 
-// sqlDBWrapper 包装 sql.DB 以实现 io.Closer
-type sqlDBWrapper struct {
-	*sql.DB
-}
-
-func (w *sqlDBWrapper) Close() error {
-	return w.DB.Close()
-}
-
 // classifyMySQLErrorType MySQL错误分类
 func classifyMySQLErrorType(err error) ErrorType {
 	if err == nil {
diff --git a/plugins/services/oracle.go b/plugins/services/oracle.go
index 87c2703..4125ea9 100644
--- a/plugins/services/oracle.go
+++ b/plugins/services/oracle.go
@@ -106,7 +106,7 @@ func (p *OraclePlugin) doOracleAuth(ctx context.Context, info *common.HostInfo,
 
 		return &AuthResult{
 			Success:   true,
-			Conn:      &oracleDBWrapper{db},
+			Conn:      &SQLDBWrapper{db},
 			ErrorType: ErrorTypeUnknown,
 			Error:     nil,
 		}
@@ -120,15 +120,6 @@ func (p *OraclePlugin) doOracleAuth(ctx context.Context, info *common.HostInfo,
 	}
 }
 
-// oracleDBWrapper 包装 sql.DB 以实现 io.Closer
-type oracleDBWrapper struct {
-	*sql.DB
-}
-
-func (w *oracleDBWrapper) Close() error {
-	return w.DB.Close()
-}
-
 // classifyOracleErrorType Oracle错误分类
 func classifyOracleErrorType(err error) ErrorType {
 	if err == nil {
diff --git a/plugins/services/postgresql.go b/plugins/services/postgresql.go
index 1777a0d..e5ecc69 100644
--- a/plugins/services/postgresql.go
+++ b/plugins/services/postgresql.go
@@ -104,21 +104,12 @@ func (p *PostgreSQLPlugin) doPostgreSQLAuth(ctx context.Context, info *common.Ho
 
 	return &AuthResult{
 		Success:   true,
-		Conn:      &pgDBWrapper{db},
+		Conn:      &SQLDBWrapper{db},
 		ErrorType: ErrorTypeUnknown,
 		Error:     nil,
 	}
 }
 
-// pgDBWrapper 包装 sql.DB 以实现 io.Closer
-type pgDBWrapper struct {
-	*sql.DB
-}
-
-func (w *pgDBWrapper) Close() error {
-	return w.DB.Close()
-}
-
 // classifyPostgreSQLErrorType PostgreSQL错误分类
 func classifyPostgreSQLErrorType(err error) ErrorType {
 	if err == nil {