diff --git a/pkg/reflection/model_utils.go b/pkg/reflection/model_utils.go
index 2a25085..2fda683 100644
--- a/pkg/reflection/model_utils.go
+++ b/pkg/reflection/model_utils.go
@@ -1,6 +1,7 @@
 package reflection
 
 import (
+	"encoding/json"
 	"fmt"
 	"reflect"
 	"strconv"
@@ -897,6 +898,319 @@ func GetRelationModel(model interface{}, fieldName string) interface{} {
 	return currentModel
 }
 
+// MapToStruct populates a struct from a map while preserving custom types
+// It uses reflection to set struct fields based on map keys, matching by:
+// 1. Bun tag column name
+// 2. Gorm tag column name
+// 3. JSON tag name
+// 4. Field name (case-insensitive)
+// This preserves custom types that implement driver.Valuer like SqlJSONB
+func MapToStruct(dataMap map[string]interface{}, target interface{}) error {
+	if dataMap == nil || target == nil {
+		return fmt.Errorf("dataMap and target cannot be nil")
+	}
+
+	targetValue := reflect.ValueOf(target)
+	if targetValue.Kind() != reflect.Ptr {
+		return fmt.Errorf("target must be a pointer to a struct")
+	}
+
+	targetValue = targetValue.Elem()
+	if targetValue.Kind() != reflect.Struct {
+		return fmt.Errorf("target must be a pointer to a struct")
+	}
+
+	targetType := targetValue.Type()
+
+	// Create a map of column names to field indices for faster lookup
+	columnToField := make(map[string]int)
+	for i := 0; i < targetType.NumField(); i++ {
+		field := targetType.Field(i)
+
+		// Skip unexported fields
+		if !field.IsExported() {
+			continue
+		}
+
+		// Build list of possible column names for this field
+		var columnNames []string
+
+		// 1. Bun tag
+		if bunTag := field.Tag.Get("bun"); bunTag != "" && bunTag != "-" {
+			if colName := ExtractColumnFromBunTag(bunTag); colName != "" {
+				columnNames = append(columnNames, colName)
+			}
+		}
+
+		// 2. Gorm tag
+		if gormTag := field.Tag.Get("gorm"); gormTag != "" && gormTag != "-" {
+			if colName := ExtractColumnFromGormTag(gormTag); colName != "" {
+				columnNames = append(columnNames, colName)
+			}
+		}
+
+		// 3. JSON tag
+		if jsonTag := field.Tag.Get("json"); jsonTag != "" && jsonTag != "-" {
+			parts := strings.Split(jsonTag, ",")
+			if len(parts) > 0 && parts[0] != "" {
+				columnNames = append(columnNames, parts[0])
+			}
+		}
+
+		// 4. Field name variations
+		columnNames = append(columnNames, field.Name)
+		columnNames = append(columnNames, strings.ToLower(field.Name))
+		columnNames = append(columnNames, ToSnakeCase(field.Name))
+
+		// Map all column name variations to this field index
+		for _, colName := range columnNames {
+			columnToField[strings.ToLower(colName)] = i
+		}
+	}
+
+	// Iterate through the map and set struct fields
+	for key, value := range dataMap {
+		// Find the field index for this key
+		fieldIndex, found := columnToField[strings.ToLower(key)]
+		if !found {
+			// Skip keys that don't map to any field
+			continue
+		}
+
+		field := targetValue.Field(fieldIndex)
+		if !field.CanSet() {
+			continue
+		}
+
+		// Set the value, preserving custom types
+		if err := setFieldValue(field, value); err != nil {
+			return fmt.Errorf("failed to set field %s: %w", targetType.Field(fieldIndex).Name, err)
+		}
+	}
+
+	return nil
+}
+
+// setFieldValue sets a reflect.Value from an interface{} value, handling type conversions
+func setFieldValue(field reflect.Value, value interface{}) error {
+	if value == nil {
+		// Set zero value for nil
+		field.Set(reflect.Zero(field.Type()))
+		return nil
+	}
+
+	valueReflect := reflect.ValueOf(value)
+
+	// If types match exactly, just set it
+	if valueReflect.Type().AssignableTo(field.Type()) {
+		field.Set(valueReflect)
+		return nil
+	}
+
+	// Handle pointer fields
+	if field.Kind() == reflect.Ptr {
+		if valueReflect.Kind() != reflect.Ptr {
+			// Create a new pointer and set its value
+			newPtr := reflect.New(field.Type().Elem())
+			if err := setFieldValue(newPtr.Elem(), value); err != nil {
+				return err
+			}
+			field.Set(newPtr)
+			return nil
+		}
+	}
+
+	// Handle conversions for basic types
+	switch field.Kind() {
+	case reflect.String:
+		if str, ok := value.(string); ok {
+			field.SetString(str)
+			return nil
+		}
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		if num, ok := convertToInt64(value); ok {
+			if field.OverflowInt(num) {
+				return fmt.Errorf("integer overflow")
+			}
+			field.SetInt(num)
+			return nil
+		}
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
+		if num, ok := convertToUint64(value); ok {
+			if field.OverflowUint(num) {
+				return fmt.Errorf("unsigned integer overflow")
+			}
+			field.SetUint(num)
+			return nil
+		}
+	case reflect.Float32, reflect.Float64:
+		if num, ok := convertToFloat64(value); ok {
+			if field.OverflowFloat(num) {
+				return fmt.Errorf("float overflow")
+			}
+			field.SetFloat(num)
+			return nil
+		}
+	case reflect.Bool:
+		if b, ok := value.(bool); ok {
+			field.SetBool(b)
+			return nil
+		}
+	case reflect.Slice:
+		// Handle []byte specially (for types like SqlJSONB)
+		if field.Type().Elem().Kind() == reflect.Uint8 {
+			switch v := value.(type) {
+			case []byte:
+				field.SetBytes(v)
+				return nil
+			case string:
+				field.SetBytes([]byte(v))
+				return nil
+			case map[string]interface{}, []interface{}:
+				// Marshal complex types to JSON for SqlJSONB fields
+				jsonBytes, err := json.Marshal(v)
+				if err != nil {
+					return fmt.Errorf("failed to marshal value to JSON: %w", err)
+				}
+				field.SetBytes(jsonBytes)
+				return nil
+			}
+		}
+	}
+
+	// Handle struct types (like SqlTimeStamp, SqlDate, SqlTime which wrap SqlNull[time.Time])
+	if field.Kind() == reflect.Struct {
+		// Try to find a "Val" field (for SqlNull types) and set it
+		valField := field.FieldByName("Val")
+		if valField.IsValid() && valField.CanSet() {
+			// Also set Valid field to true
+			validField := field.FieldByName("Valid")
+			if validField.IsValid() && validField.CanSet() && validField.Kind() == reflect.Bool {
+				// Set the Val field
+				if err := setFieldValue(valField, value); err != nil {
+					return err
+				}
+				// Set Valid to true
+				validField.SetBool(true)
+				return nil
+			}
+		}
+	}
+
+	// If we can convert the type, do it
+	if valueReflect.Type().ConvertibleTo(field.Type()) {
+		field.Set(valueReflect.Convert(field.Type()))
+		return nil
+	}
+
+	return fmt.Errorf("cannot convert %v to %v", valueReflect.Type(), field.Type())
+}
+
+// convertToInt64 attempts to convert various types to int64
+func convertToInt64(value interface{}) (int64, bool) {
+	switch v := value.(type) {
+	case int:
+		return int64(v), true
+	case int8:
+		return int64(v), true
+	case int16:
+		return int64(v), true
+	case int32:
+		return int64(v), true
+	case int64:
+		return v, true
+	case uint:
+		return int64(v), true
+	case uint8:
+		return int64(v), true
+	case uint16:
+		return int64(v), true
+	case uint32:
+		return int64(v), true
+	case uint64:
+		return int64(v), true
+	case float32:
+		return int64(v), true
+	case float64:
+		return int64(v), true
+	case string:
+		if num, err := strconv.ParseInt(v, 10, 64); err == nil {
+			return num, true
+		}
+	}
+	return 0, false
+}
+
+// convertToUint64 attempts to convert various types to uint64
+func convertToUint64(value interface{}) (uint64, bool) {
+	switch v := value.(type) {
+	case int:
+		return uint64(v), true
+	case int8:
+		return uint64(v), true
+	case int16:
+		return uint64(v), true
+	case int32:
+		return uint64(v), true
+	case int64:
+		return uint64(v), true
+	case uint:
+		return uint64(v), true
+	case uint8:
+		return uint64(v), true
+	case uint16:
+		return uint64(v), true
+	case uint32:
+		return uint64(v), true
+	case uint64:
+		return v, true
+	case float32:
+		return uint64(v), true
+	case float64:
+		return uint64(v), true
+	case string:
+		if num, err := strconv.ParseUint(v, 10, 64); err == nil {
+			return num, true
+		}
+	}
+	return 0, false
+}
+
+// convertToFloat64 attempts to convert various types to float64
+func convertToFloat64(value interface{}) (float64, bool) {
+	switch v := value.(type) {
+	case int:
+		return float64(v), true
+	case int8:
+		return float64(v), true
+	case int16:
+		return float64(v), true
+	case int32:
+		return float64(v), true
+	case int64:
+		return float64(v), true
+	case uint:
+		return float64(v), true
+	case uint8:
+		return float64(v), true
+	case uint16:
+		return float64(v), true
+	case uint32:
+		return float64(v), true
+	case uint64:
+		return float64(v), true
+	case float32:
+		return float64(v), true
+	case float64:
+		return v, true
+	case string:
+		if num, err := strconv.ParseFloat(v, 64); err == nil {
+			return num, true
+		}
+	}
+	return 0, false
+}
+
 // getRelationModelSingleLevel gets the model type for a single level field (non-recursive)
 // This is a helper function used by GetRelationModel to handle one level at a time
 func getRelationModelSingleLevel(model interface{}, fieldName string) interface{} {
diff --git a/pkg/reflection/model_utils_sqltypes_test.go b/pkg/reflection/model_utils_sqltypes_test.go
new file mode 100644
index 0000000..030c6d4
--- /dev/null
+++ b/pkg/reflection/model_utils_sqltypes_test.go
@@ -0,0 +1,266 @@
+package reflection_test
+
+import (
+	"testing"
+	"time"
+
+	"github.com/bitechdev/ResolveSpec/pkg/common"
+	"github.com/bitechdev/ResolveSpec/pkg/reflection"
+)
+
+func TestMapToStruct_SqlJSONB_PreservesDriverValuer(t *testing.T) {
+	// Test that SqlJSONB type preserves driver.Valuer interface
+	type TestModel struct {
+		ID   int64           `bun:"id,pk" json:"id"`
+		Meta common.SqlJSONB `bun:"meta" json:"meta"`
+	}
+
+	dataMap := map[string]interface{}{
+		"id": int64(123),
+		"meta": map[string]interface{}{
+			"key": "value",
+			"num": 42,
+		},
+	}
+
+	var result TestModel
+	err := reflection.MapToStruct(dataMap, &result)
+	if err != nil {
+		t.Fatalf("MapToStruct() error = %v", err)
+	}
+
+	// Verify the field was set
+	if result.ID != 123 {
+		t.Errorf("ID = %v, want 123", result.ID)
+	}
+
+	// Verify SqlJSONB was populated
+	if len(result.Meta) == 0 {
+		t.Error("Meta is empty, want non-empty")
+	}
+
+	// Most importantly: verify driver.Valuer interface works
+	value, err := result.Meta.Value()
+	if err != nil {
+		t.Errorf("Meta.Value() error = %v, want nil", err)
+	}
+
+	// Value should return a string representation of the JSON
+	if value == nil {
+		t.Error("Meta.Value() returned nil, want non-nil")
+	}
+
+	// Check it's a valid JSON string
+	if str, ok := value.(string); ok {
+		if len(str) == 0 {
+			t.Error("Meta.Value() returned empty string, want valid JSON")
+		}
+		t.Logf("SqlJSONB.Value() returned: %s", str)
+	} else {
+		t.Errorf("Meta.Value() returned type %T, want string", value)
+	}
+}
+
+func TestMapToStruct_SqlJSONB_FromBytes(t *testing.T) {
+	// Test that SqlJSONB can be set from []byte directly
+	type TestModel struct {
+		ID   int64           `bun:"id,pk" json:"id"`
+		Meta common.SqlJSONB `bun:"meta" json:"meta"`
+	}
+
+	jsonBytes := []byte(`{"direct":"bytes"}`)
+	dataMap := map[string]interface{}{
+		"id":   int64(456),
+		"meta": jsonBytes,
+	}
+
+	var result TestModel
+	err := reflection.MapToStruct(dataMap, &result)
+	if err != nil {
+		t.Fatalf("MapToStruct() error = %v", err)
+	}
+
+	if result.ID != 456 {
+		t.Errorf("ID = %v, want 456", result.ID)
+	}
+
+	if string(result.Meta) != string(jsonBytes) {
+		t.Errorf("Meta = %s, want %s", string(result.Meta), string(jsonBytes))
+	}
+
+	// Verify driver.Valuer works
+	value, err := result.Meta.Value()
+	if err != nil {
+		t.Errorf("Meta.Value() error = %v", err)
+	}
+	if value == nil {
+		t.Error("Meta.Value() returned nil")
+	}
+}
+
+func TestMapToStruct_AllSqlTypes(t *testing.T) {
+	// Test model with all SQL custom types
+	type TestModel struct {
+		ID        int64               `bun:"id,pk" json:"id"`
+		Name      string              `bun:"name" json:"name"`
+		CreatedAt common.SqlTimeStamp `bun:"created_at" json:"created_at"`
+		BirthDate common.SqlDate      `bun:"birth_date" json:"birth_date"`
+		LoginTime common.SqlTime      `bun:"login_time" json:"login_time"`
+		Meta      common.SqlJSONB     `bun:"meta" json:"meta"`
+		Tags      common.SqlJSONB     `bun:"tags" json:"tags"`
+	}
+
+	now := time.Now()
+	birthDate := time.Date(1990, 1, 15, 0, 0, 0, 0, time.UTC)
+	loginTime := time.Date(0, 1, 1, 14, 30, 0, 0, time.UTC)
+
+	dataMap := map[string]interface{}{
+		"id":         int64(100),
+		"name":       "Test User",
+		"created_at": now,
+		"birth_date": birthDate,
+		"login_time": loginTime,
+		"meta": map[string]interface{}{
+			"role":   "admin",
+			"active": true,
+		},
+		"tags": []interface{}{"golang", "testing", "sql"},
+	}
+
+	var result TestModel
+	err := reflection.MapToStruct(dataMap, &result)
+	if err != nil {
+		t.Fatalf("MapToStruct() error = %v", err)
+	}
+
+	// Verify basic fields
+	if result.ID != 100 {
+		t.Errorf("ID = %v, want 100", result.ID)
+	}
+	if result.Name != "Test User" {
+		t.Errorf("Name = %v, want 'Test User'", result.Name)
+	}
+
+	// Verify SqlTimeStamp
+	if !result.CreatedAt.Valid {
+		t.Error("CreatedAt.Valid = false, want true")
+	}
+	if !result.CreatedAt.Val.Equal(now) {
+		t.Errorf("CreatedAt.Val = %v, want %v", result.CreatedAt.Val, now)
+	}
+
+	// Verify driver.Valuer for SqlTimeStamp
+	tsValue, err := result.CreatedAt.Value()
+	if err != nil {
+		t.Errorf("CreatedAt.Value() error = %v", err)
+	}
+	if tsValue == nil {
+		t.Error("CreatedAt.Value() returned nil")
+	}
+
+	// Verify SqlDate
+	if !result.BirthDate.Valid {
+		t.Error("BirthDate.Valid = false, want true")
+	}
+	if !result.BirthDate.Val.Equal(birthDate) {
+		t.Errorf("BirthDate.Val = %v, want %v", result.BirthDate.Val, birthDate)
+	}
+
+	// Verify driver.Valuer for SqlDate
+	dateValue, err := result.BirthDate.Value()
+	if err != nil {
+		t.Errorf("BirthDate.Value() error = %v", err)
+	}
+	if dateValue == nil {
+		t.Error("BirthDate.Value() returned nil")
+	}
+
+	// Verify SqlTime
+	if !result.LoginTime.Valid {
+		t.Error("LoginTime.Valid = false, want true")
+	}
+
+	// Verify driver.Valuer for SqlTime
+	timeValue, err := result.LoginTime.Value()
+	if err != nil {
+		t.Errorf("LoginTime.Value() error = %v", err)
+	}
+	if timeValue == nil {
+		t.Error("LoginTime.Value() returned nil")
+	}
+
+	// Verify SqlJSONB for Meta
+	if len(result.Meta) == 0 {
+		t.Error("Meta is empty")
+	}
+	metaValue, err := result.Meta.Value()
+	if err != nil {
+		t.Errorf("Meta.Value() error = %v", err)
+	}
+	if metaValue == nil {
+		t.Error("Meta.Value() returned nil")
+	}
+
+	// Verify SqlJSONB for Tags
+	if len(result.Tags) == 0 {
+		t.Error("Tags is empty")
+	}
+	tagsValue, err := result.Tags.Value()
+	if err != nil {
+		t.Errorf("Tags.Value() error = %v", err)
+	}
+	if tagsValue == nil {
+		t.Error("Tags.Value() returned nil")
+	}
+
+	t.Logf("All SQL types successfully preserved driver.Valuer interface:")
+	t.Logf("  - SqlTimeStamp: %v", tsValue)
+	t.Logf("  - SqlDate: %v", dateValue)
+	t.Logf("  - SqlTime: %v", timeValue)
+	t.Logf("  - SqlJSONB (Meta): %v", metaValue)
+	t.Logf("  - SqlJSONB (Tags): %v", tagsValue)
+}
+
+func TestMapToStruct_SqlNull_NilValues(t *testing.T) {
+	// Test that SqlNull types handle nil values correctly
+	type TestModel struct {
+		ID        int64               `bun:"id,pk" json:"id"`
+		UpdatedAt common.SqlTimeStamp `bun:"updated_at" json:"updated_at"`
+		DeletedAt common.SqlTimeStamp `bun:"deleted_at" json:"deleted_at"`
+	}
+
+	now := time.Now()
+	dataMap := map[string]interface{}{
+		"id":         int64(200),
+		"updated_at": now,
+		"deleted_at": nil, // Explicitly nil
+	}
+
+	var result TestModel
+	err := reflection.MapToStruct(dataMap, &result)
+	if err != nil {
+		t.Fatalf("MapToStruct() error = %v", err)
+	}
+
+	// UpdatedAt should be valid
+	if !result.UpdatedAt.Valid {
+		t.Error("UpdatedAt.Valid = false, want true")
+	}
+	if !result.UpdatedAt.Val.Equal(now) {
+		t.Errorf("UpdatedAt.Val = %v, want %v", result.UpdatedAt.Val, now)
+	}
+
+	// DeletedAt should be invalid (null)
+	if result.DeletedAt.Valid {
+		t.Error("DeletedAt.Valid = true, want false (null)")
+	}
+
+	// Verify driver.Valuer for null SqlTimeStamp
+	deletedValue, err := result.DeletedAt.Value()
+	if err != nil {
+		t.Errorf("DeletedAt.Value() error = %v", err)
+	}
+	if deletedValue != nil {
+		t.Errorf("DeletedAt.Value() = %v, want nil", deletedValue)
+	}
+}
diff --git a/pkg/reflection/model_utils_test.go b/pkg/reflection/model_utils_test.go
index 8aa3db6..41b6529 100644
--- a/pkg/reflection/model_utils_test.go
+++ b/pkg/reflection/model_utils_test.go
@@ -1687,3 +1687,201 @@ func TestGetRelationModel_WithTags(t *testing.T) {
 		})
 	}
 }
+
+func TestMapToStruct(t *testing.T) {
+	// Test model with various field types
+	type TestModel struct {
+		ID       int64   `bun:"id,pk" json:"id"`
+		Name     string  `bun:"name" json:"name"`
+		Age      int     `bun:"age" json:"age"`
+		Active   bool    `bun:"active" json:"active"`
+		Score    float64 `bun:"score" json:"score"`
+		Data     []byte  `bun:"data" json:"data"`
+		MetaJSON []byte  `bun:"meta_json" json:"meta_json"`
+	}
+
+	tests := []struct {
+		name     string
+		dataMap  map[string]interface{}
+		expected TestModel
+		wantErr  bool
+	}{
+		{
+			name: "Basic types conversion",
+			dataMap: map[string]interface{}{
+				"id":     int64(123),
+				"name":   "Test User",
+				"age":    30,
+				"active": true,
+				"score":  95.5,
+			},
+			expected: TestModel{
+				ID:     123,
+				Name:   "Test User",
+				Age:    30,
+				Active: true,
+				Score:  95.5,
+			},
+			wantErr: false,
+		},
+		{
+			name: "Byte slice (SqlJSONB-like) from []byte",
+			dataMap: map[string]interface{}{
+				"id":   int64(456),
+				"name": "JSON Test",
+				"data": []byte(`{"key":"value"}`),
+			},
+			expected: TestModel{
+				ID:   456,
+				Name: "JSON Test",
+				Data: []byte(`{"key":"value"}`),
+			},
+			wantErr: false,
+		},
+		{
+			name: "Byte slice from string",
+			dataMap: map[string]interface{}{
+				"id":   int64(789),
+				"data": "string data",
+			},
+			expected: TestModel{
+				ID:   789,
+				Data: []byte("string data"),
+			},
+			wantErr: false,
+		},
+		{
+			name: "Byte slice from map (JSON marshal)",
+			dataMap: map[string]interface{}{
+				"id": int64(999),
+				"meta_json": map[string]interface{}{
+					"field1": "value1",
+					"field2": 42,
+				},
+			},
+			expected: TestModel{
+				ID:       999,
+				MetaJSON: []byte(`{"field1":"value1","field2":42}`),
+			},
+			wantErr: false,
+		},
+		{
+			name: "Byte slice from slice (JSON marshal)",
+			dataMap: map[string]interface{}{
+				"id":        int64(111),
+				"meta_json": []interface{}{"item1", "item2", 3},
+			},
+			expected: TestModel{
+				ID:       111,
+				MetaJSON: []byte(`["item1","item2",3]`),
+			},
+			wantErr: false,
+		},
+		{
+			name: "Field matching by bun tag",
+			dataMap: map[string]interface{}{
+				"id":   int64(222),
+				"name": "Tagged Field",
+			},
+			expected: TestModel{
+				ID:   222,
+				Name: "Tagged Field",
+			},
+			wantErr: false,
+		},
+		{
+			name: "Nil values",
+			dataMap: map[string]interface{}{
+				"id":   int64(333),
+				"data": nil,
+			},
+			expected: TestModel{
+				ID:   333,
+				Data: nil,
+			},
+			wantErr: false,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			var result TestModel
+			err := MapToStruct(tt.dataMap, &result)
+
+			if (err != nil) != tt.wantErr {
+				t.Errorf("MapToStruct() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+
+			// Compare fields individually for better error messages
+			if result.ID != tt.expected.ID {
+				t.Errorf("ID = %v, want %v", result.ID, tt.expected.ID)
+			}
+			if result.Name != tt.expected.Name {
+				t.Errorf("Name = %v, want %v", result.Name, tt.expected.Name)
+			}
+			if result.Age != tt.expected.Age {
+				t.Errorf("Age = %v, want %v", result.Age, tt.expected.Age)
+			}
+			if result.Active != tt.expected.Active {
+				t.Errorf("Active = %v, want %v", result.Active, tt.expected.Active)
+			}
+			if result.Score != tt.expected.Score {
+				t.Errorf("Score = %v, want %v", result.Score, tt.expected.Score)
+			}
+
+			// For byte slices, compare as strings for JSON data
+			if tt.expected.Data != nil {
+				if string(result.Data) != string(tt.expected.Data) {
+					t.Errorf("Data = %s, want %s", string(result.Data), string(tt.expected.Data))
+				}
+			}
+			if tt.expected.MetaJSON != nil {
+				if string(result.MetaJSON) != string(tt.expected.MetaJSON) {
+					t.Errorf("MetaJSON = %s, want %s", string(result.MetaJSON), string(tt.expected.MetaJSON))
+				}
+			}
+		})
+	}
+}
+
+func TestMapToStruct_Errors(t *testing.T) {
+	type TestModel struct {
+		ID int `bun:"id" json:"id"`
+	}
+
+	tests := []struct {
+		name    string
+		dataMap map[string]interface{}
+		target  interface{}
+		wantErr bool
+	}{
+		{
+			name:    "Nil dataMap",
+			dataMap: nil,
+			target:  &TestModel{},
+			wantErr: true,
+		},
+		{
+			name:    "Nil target",
+			dataMap: map[string]interface{}{"id": 1},
+			target:  nil,
+			wantErr: true,
+		},
+		{
+			name:    "Non-pointer target",
+			dataMap: map[string]interface{}{"id": 1},
+			target:  TestModel{},
+			wantErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			err := MapToStruct(tt.dataMap, tt.target)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("MapToStruct() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}
diff --git a/pkg/restheadspec/handler.go b/pkg/restheadspec/handler.go
index acb1833..ce6bb64 100644
--- a/pkg/restheadspec/handler.go
+++ b/pkg/restheadspec/handler.go
@@ -1220,8 +1220,14 @@ func (h *Handler) handleUpdate(ctx context.Context, w common.ResponseWriter, id
 		// Ensure ID is in the data map for the update
 		dataMap[pkName] = targetID
 
-		// Create update query
-		query := tx.NewUpdate().Table(tableName).SetMap(dataMap)
+		// Populate model instance from dataMap to preserve custom types (like SqlJSONB)
+		modelInstance := reflect.New(reflect.TypeOf(model).Elem()).Interface()
+		if err := reflection.MapToStruct(dataMap, modelInstance); err != nil {
+			return fmt.Errorf("failed to populate model from data: %w", err)
+		}
+
+		// Create update query using Model() to preserve custom types and driver.Valuer interfaces
+		query := tx.NewUpdate().Model(modelInstance).Table(tableName)
 		query = query.Where(fmt.Sprintf("%s = ?", common.QuoteIdent(pkName)), targetID)
 
 		// Execute BeforeScan hooks - pass query chain so hooks can modify it