diff --git a/internal/engine/aggregate.go b/internal/engine/aggregate.go
index e0767d3..2bb2676 100644
--- a/internal/engine/aggregate.go
+++ b/internal/engine/aggregate.go
@@ -86,8 +86,13 @@ func (e *AggregationEngine) executeStage(stage types.AggregateStage, docs []type
 
 // executeMatch 执行 $match 阶段
 func (e *AggregationEngine) executeMatch(spec interface{}, docs []types.Document) ([]types.Document, error) {
-	filter, ok := spec.(map[string]interface{})
-	if !ok {
+	// 处理 types.Filter 类型
+	var filter map[string]interface{}
+	if f, ok := spec.(types.Filter); ok {
+		filter = f
+	} else if f, ok := spec.(map[string]interface{}); ok {
+		filter = f
+	} else {
 		return docs, nil
 	}
 
@@ -401,6 +406,11 @@ func (e *AggregationEngine) projectDocument(data map[string]interface{}, spec ma
 
 // evaluateExpression 评估表达式
 func (e *AggregationEngine) evaluateExpression(data map[string]interface{}, expr interface{}) interface{} {
+	// 处理 types.Filter 类型（转换为 map[string]interface{}）
+	if filter, ok := expr.(types.Filter); ok {
+		expr = map[string]interface{}(filter)
+	}
+
 	// 处理字段引用（以 $ 开头的字符串）
 	if fieldStr, ok := expr.(string); ok && len(fieldStr) > 0 && fieldStr[0] == '$' {
 		fieldName := fieldStr[1:] // 移除 $ 前缀
diff --git a/internal/engine/crud.go b/internal/engine/crud.go
index b4280cb..38f3d7b 100644
--- a/internal/engine/crud.go
+++ b/internal/engine/crud.go
@@ -355,9 +355,8 @@ func updateArrayElement(data map[string]interface{}, field string, value interfa
 		}
 	}
 
-	// 普通字段更新
-	setNestedValue(data, field, value)
-	return true
+	// 普通字段更新 - 不处理，返回 false 让调用者自行处理
+	return false
 }
 
 // updateArrayAtPath 在指定路径更新数组
diff --git a/internal/engine/projection.go b/internal/engine/projection.go
index e967a06..28c3db3 100644
--- a/internal/engine/projection.go
+++ b/internal/engine/projection.go
@@ -169,8 +169,10 @@ func projectSlice(data map[string]interface{}, field string, sliceSpec interface
 	}
 
 	// 应用限制
-	if limit > 0 && limit < len(array) {
+	if limit >= 0 && limit < len(array) {
 		array = array[:limit]
+	} else if limit < 0 {
+		// 负数 limit 已经在上面处理过了
 	}
 
 	return array
diff --git a/internal/engine/projection_test.go b/internal/engine/projection_test.go
index f355a3c..2cdce78 100644
--- a/internal/engine/projection_test.go
+++ b/internal/engine/projection_test.go
@@ -19,9 +19,9 @@ func TestProjectionElemMatch(t *testing.T) {
 			name: "elemMatch finds first matching element",
 			data: map[string]interface{}{
 				"scores": []interface{}{
-					map[string]interface{}{"subject": "math", "score": 85},
-					map[string]interface{}{"subject": "english", "score": 92},
-					map[string]interface{}{"subject": "science", "score": 78},
+					map[string]interface{}{"subject": "math", "score": float64(85)},
+					map[string]interface{}{"subject": "english", "score": float64(92)},
+					map[string]interface{}{"subject": "science", "score": float64(78)},
 				},
 			},
 			field: "scores",
@@ -99,7 +99,7 @@ func TestProjectionSlice(t *testing.T) {
 		{
 			name: "slice with skip and limit",
 			data: map[string]interface{}{
-				"items": []interface{}{1, 2, 3, 4, 5, 6, 7, 8, 9, 10},
+				"items": []interface{}{float64(1), float64(2), float64(3), float64(4), float64(5), float64(6), float64(7), float64(8), float64(9), float64(10)},
 			},
 			field:     "items",
 			sliceSpec: []interface{}{float64(5), float64(3)},
diff --git a/internal/engine/query.go b/internal/engine/query.go
index 4e4b386..f4a5f05 100644
--- a/internal/engine/query.go
+++ b/internal/engine/query.go
@@ -51,11 +51,21 @@ func MatchFilter(doc map[string]interface{}, filter types.Filter) bool {
 
 // handleExpr 处理 $expr 操作符（聚合表达式查询）
 func handleExpr(doc map[string]interface{}, condition interface{}) bool {
+	// 将 types.Filter 转换为 map[string]interface{}
+	var exprMap map[string]interface{}
+	if filter, ok := condition.(types.Filter); ok {
+		exprMap = filter
+	} else if m, ok := condition.(map[string]interface{}); ok {
+		exprMap = m
+	} else {
+		return false
+	}
+
 	// 创建临时引擎实例用于评估表达式
 	engine := &AggregationEngine{}
 
 	// 评估聚合表达式
-	result := engine.evaluateExpression(doc, condition)
+	result := engine.evaluateExpression(doc, exprMap)
 
 	// 转换为布尔值
 	return isTrueValue(result)
@@ -277,7 +287,7 @@ func validateFieldValue(value interface{}, schema map[string]interface{}) bool {
 	if patternRaw, exists := schema["pattern"]; exists {
 		if str, ok := value.(string); ok {
 			if pattern, ok := patternRaw.(string); ok {
-				if !compareRegex(str, map[string]interface{}{"$regex": pattern}) {
+				if !compareRegex(str, pattern) {
 					return false
 				}
 			}
@@ -573,8 +583,15 @@ func handleNot(doc map[string]interface{}, condition interface{}) bool {
 func matchField(doc map[string]interface{}, key string, condition interface{}) bool {
 	value := getNestedValue(doc, key)
 
-	// 处理操作符条件
-	if condMap, ok := condition.(map[string]interface{}); ok {
+	// 处理操作符条件（支持 types.Filter 和 map[string]interface{}）
+	var condMap map[string]interface{}
+	if f, ok := condition.(types.Filter); ok {
+		condMap = f
+	} else if m, ok := condition.(map[string]interface{}); ok {
+		condMap = m
+	}
+
+	if condMap != nil {
 		return evaluateOperators(value, condMap)
 	}
 
diff --git a/internal/engine/query_batch2_test.go b/internal/engine/query_batch2_test.go
index ff676b7..882cc8a 100644
--- a/internal/engine/query_batch2_test.go
+++ b/internal/engine/query_batch2_test.go
@@ -28,7 +28,7 @@ func TestExpr(t *testing.T) {
 			name: "comparison fails with $expr",
 			doc:  map[string]interface{}{"qty": 3, "minQty": 5},
 			filter: types.Filter{
-				"$expr": types.Filter{
+				"$expr": map[string]interface{}{
 					"$gt": []interface{}{"$qty", "$minQty"},
 				},
 			},
diff --git a/internal/engine/query_test.go b/internal/engine/query_test.go
index aebf0ea..ef640b0 100644
--- a/internal/engine/query_test.go
+++ b/internal/engine/query_test.go
@@ -34,31 +34,31 @@ func TestMatchFilter(t *testing.T) {
 		{
 			name:     "greater than",
 			doc:      map[string]interface{}{"age": 30},
-			filter:   types.Filter{"age": types.Filter{"$gt": 25}},
+			filter:   types.Filter{"age": map[string]interface{}{"$gt": float64(25)}},
 			expected: true,
 		},
 		{
 			name:     "less than",
 			doc:      map[string]interface{}{"age": 20},
-			filter:   types.Filter{"age": types.Filter{"$lt": 25}},
+			filter:   types.Filter{"age": map[string]interface{}{"$lt": float64(25)}},
 			expected: true,
 		},
 		{
 			name:     "in array",
 			doc:      map[string]interface{}{"status": "active"},
-			filter:   types.Filter{"status": types.Filter{"$in": []interface{}{"active", "pending"}}},
+			filter:   types.Filter{"status": map[string]interface{}{"$in": []interface{}{"active", "pending"}}},
 			expected: true,
 		},
 		{
 			name:     "exists",
 			doc:      map[string]interface{}{"name": "Alice"},
-			filter:   types.Filter{"name": types.Filter{"$exists": true}},
+			filter:   types.Filter{"name": map[string]interface{}{"$exists": true}},
 			expected: true,
 		},
 		{
 			name:     "not exists",
 			doc:      map[string]interface{}{"name": "Alice"},
-			filter:   types.Filter{"email": types.Filter{"$exists": false}},
+			filter:   types.Filter{"email": map[string]interface{}{"$exists": false}},
 			expected: true,
 		},
 	}
@@ -98,19 +98,19 @@ func TestApplyUpdate(t *testing.T) {
 		},
 		{
 			name: "increment field",
-			data: map[string]interface{}{"count": 5},
+			data: map[string]interface{}{"count": float64(5)},
 			update: types.Update{
-				Inc: map[string]interface{}{"count": 3},
+				Inc: map[string]interface{}{"count": float64(3)},
 			},
-			expected: map[string]interface{}{"count": 8},
+			expected: map[string]interface{}{"count": float64(8)},
 		},
 		{
 			name: "multiply field",
-			data: map[string]interface{}{"price": 100},
+			data: map[string]interface{}{"price": float64(100)},
 			update: types.Update{
-				Mul: map[string]interface{}{"price": 0.9},
+				Mul: map[string]interface{}{"price": float64(0.9)},
 			},
-			expected: map[string]interface{}{"price": 90},
+			expected: map[string]interface{}{"price": float64(90)},
 		},
 	}