✨ feat(data-grid): 增强数据表编辑与展示体验

- 新增变更预览能力，支持在提交前查看删除、更新和新增对应的 SQL 语句
- 增加表格密度配置，统一控制默认列宽、行高、字号与单元格内边距
- 优化 DataGrid 编辑状态展示，区分新增、修改和删除行列的视觉反馈
- 调整导出入口与 Wails 前端绑定，补齐变更预览相关调用与测试覆盖

internal/app/methods_file.go

@@ -1012,6 +1012,35 @@ func (a *App) ApplyChanges(config connection.ConnectionConfig, dbName, tableName
 	return connection.QueryResult{Success: false, Message: "当前数据库类型不支持批量提交"}
 }
 
+// ChangePreview 变更预览结果
+type ChangePreview struct {
+	Deletes []string `json:"deletes"`
+	Updates []string `json:"updates"`
+	Inserts []string `json:"inserts"`
+}
+
+func (a *App) PreviewChanges(config connection.ConnectionConfig, dbName, tableName string, changes connection.ChangeSet) connection.QueryResult {
+	runConfig := normalizeRunConfig(config, dbName)
+
+	dbInst, err := a.getDatabase(runConfig)
+	if err != nil {
+		return connection.QueryResult{Success: false, Message: err.Error()}
+	}
+
+	var cp ChangePreview
+	// 优先使用驱动的 PreviewChanges（若实现了 ChangePreviewer 接口）
+	if previewer, ok := dbInst.(db.ChangePreviewer); ok {
+		deletes, updates, inserts := previewer.PreviewChanges(tableName, changes)
+		cp = ChangePreview{Deletes: deletes, Updates: updates, Inserts: inserts}
+	} else {
+		// 回退到通用生成，使用 quoteIdentByType 处理标识符转义
+		quoter := func(s string) string { return quoteIdentByType(runConfig.Type, s) }
+		deletes, updates, inserts := db.GenerateChangePreview(tableName, changes, quoter)
+		cp = ChangePreview{Deletes: deletes, Updates: updates, Inserts: inserts}
+	}
+	return connection.QueryResult{Success: true, Data: cp}
+}
+
 func (a *App) ExportTable(config connection.ConnectionConfig, dbName string, tableName string, format string) connection.QueryResult {
 	filename, err := runtime.SaveFileDialog(a.ctx, runtime.SaveDialogOptions{
 		Title:           fmt.Sprintf("Export %s", tableName),

internal/db/change_preview.go

@@ -0,0 +1,135 @@
+package db
+
+import (
+	"fmt"
+	"sort"
+	"strings"
+	"time"
+
+	"GoNavi-Wails/internal/connection"
+)
+
+// GenerateChangePreview 将 ChangeSet 转为可读 SQL 语句（不执行）。
+// quoteIdent 用于引用列名/表名（MySQL: backtick, PostgreSQL: double quote）。
+func GenerateChangePreview(tableName string, changes connection.ChangeSet, quoteIdent func(string) string) (deletes, updates, inserts []string) {
+	qt := quoteIdent
+
+	// Deletes
+	for _, pk := range changes.Deletes {
+		var conds []string
+		for _, k := range sortedKeys(pk) {
+			v := pk[k]
+			conds = append(conds, fmt.Sprintf("%s = %s", qt(k), formatLiteral(v)))
+		}
+		if len(conds) > 0 {
+			deletes = append(deletes, fmt.Sprintf("DELETE FROM %s WHERE %s;", qt(tableName), strings.Join(conds, " AND ")))
+		}
+	}
+
+	// Updates
+	for _, row := range changes.Updates {
+		var sets []string
+		for _, k := range sortedKeys(row.Values) {
+			v := row.Values[k]
+			sets = append(sets, fmt.Sprintf("%s = %s", qt(k), formatLiteral(v)))
+		}
+		if len(sets) == 0 {
+			continue
+		}
+		var conds []string
+		for _, k := range sortedKeys(row.Keys) {
+			v := row.Keys[k]
+			conds = append(conds, fmt.Sprintf("%s = %s", qt(k), formatLiteral(v)))
+		}
+		if len(conds) == 0 {
+			continue
+		}
+		updates = append(updates, fmt.Sprintf("UPDATE %s SET %s WHERE %s;", qt(tableName), strings.Join(sets, ", "), strings.Join(conds, " AND ")))
+	}
+
+	// Inserts
+	for _, row := range changes.Inserts {
+		var cols []string
+		var vals []string
+		for _, k := range sortedKeys(row) {
+			v := row[k]
+			if v == nil {
+				continue
+			}
+			cols = append(cols, qt(k))
+			vals = append(vals, formatLiteral(v))
+		}
+		if len(cols) == 0 {
+			continue
+		}
+		inserts = append(inserts, fmt.Sprintf("INSERT INTO %s (%s) VALUES (%s);", qt(tableName), strings.Join(cols, ", "), strings.Join(vals, ", ")))
+	}
+
+	return deletes, updates, inserts
+}
+
+// sortedKeys 返回 map 的键排序切片，保证输出确定性。
+func sortedKeys(m map[string]interface{}) []string {
+	keys := make([]string, 0, len(m))
+	for k := range m {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+	return keys
+}
+
+// formatLiteral 将 Go 值转为 SQL 字面量字符串。
+func formatLiteral(v interface{}) string {
+	if v == nil {
+		return "NULL"
+	}
+	switch t := v.(type) {
+	case string:
+		escaped := strings.ReplaceAll(t, "\\", "\\\\")
+		escaped = strings.ReplaceAll(escaped, "'", "\\'")
+		return fmt.Sprintf("'%s'", escaped)
+	case float64:
+		return formatNumber(t)
+	case float32:
+		return formatNumber(float64(t))
+	case int:
+		return fmt.Sprintf("%d", t)
+	case int64:
+		return fmt.Sprintf("%d", t)
+	case int32:
+		return fmt.Sprintf("%d", t)
+	case int16:
+		return fmt.Sprintf("%d", t)
+	case int8:
+		return fmt.Sprintf("%d", t)
+	case uint64:
+		return fmt.Sprintf("%d", t)
+	case uint32:
+		return fmt.Sprintf("%d", t)
+	case uint16:
+		return fmt.Sprintf("%d", t)
+	case uint8:
+		return fmt.Sprintf("%d", t)
+	case uint:
+		return fmt.Sprintf("%d", t)
+	case time.Time:
+		return fmt.Sprintf("'%s'", t.Format("2006-01-02 15:04:05"))
+	case bool:
+		if t {
+			return "TRUE"
+		}
+		return "FALSE"
+	case []byte:
+		return formatLiteral(string(t))
+	default:
+		escaped := strings.ReplaceAll(fmt.Sprintf("%v", t), "'", "\\'")
+		return fmt.Sprintf("'%s'", escaped)
+	}
+}
+
+func formatNumber(f float64) string {
+	if f == float64(int64(f)) {
+		return fmt.Sprintf("%d", int64(f))
+	}
+	return fmt.Sprintf("%v", f)
+}

internal/db/change_preview_test.go

@@ -0,0 +1,113 @@
+package db
+
+import (
+	"strings"
+	"testing"
+
+	"GoNavi-Wails/internal/connection"
+)
+
+func TestGenerateChangePreview_Inserts(t *testing.T) {
+	changes := connection.ChangeSet{
+		Inserts: []map[string]interface{}{
+			{"name": "alice", "age": float64(30)},
+			{"name": "bob", "age": nil},
+		},
+	}
+	deletes, updates, inserts := GenerateChangePreview("users", changes, mysqlQuote)
+	if len(inserts) != 2 {
+		t.Fatalf("expected 2 inserts, got %d", len(inserts))
+	}
+	expected1 := "INSERT INTO `users` (`age`, `name`) VALUES (30, 'alice');"
+	expected2 := "INSERT INTO `users` (`name`) VALUES ('bob');"
+	if inserts[0] != expected1 {
+		t.Errorf("insert[0]: got  %s\nwant %s", inserts[0], expected1)
+	}
+	if inserts[1] != expected2 {
+		t.Errorf("insert[1]: got  %s\nwant %s", inserts[1], expected2)
+	}
+	if len(deletes) != 0 || len(updates) != 0 {
+		t.Errorf("expected empty deletes/updates")
+	}
+}
+
+func TestGenerateChangePreview_Deletes(t *testing.T) {
+	changes := connection.ChangeSet{
+		Deletes: []map[string]interface{}{
+			{"id": float64(1), "name": "alice"},
+			{"id": float64(2)},
+		},
+	}
+	deletes, updates, inserts := GenerateChangePreview("users", changes, mysqlQuote)
+	if len(deletes) != 2 {
+		t.Fatalf("expected 2 deletes, got %d", len(deletes))
+	}
+	expected1 := "DELETE FROM `users` WHERE `id` = 1 AND `name` = 'alice';"
+	if deletes[0] != expected1 {
+		t.Errorf("delete[0]: got  %s\nwant %s", deletes[0], expected1)
+	}
+	if len(updates) != 0 || len(inserts) != 0 {
+		t.Errorf("expected empty updates/inserts")
+	}
+}
+
+func TestGenerateChangePreview_Updates(t *testing.T) {
+	changes := connection.ChangeSet{
+		Updates: []connection.UpdateRow{
+			{
+				Keys:   map[string]interface{}{"id": float64(1)},
+				Values: map[string]interface{}{"name": "charlie", "age": float64(25)},
+			},
+		},
+	}
+	deletes, updates, inserts := GenerateChangePreview("users", changes, mysqlQuote)
+	if len(updates) != 1 {
+		t.Fatalf("expected 1 update, got %d", len(updates))
+	}
+	// SET clause column order is map-iteration-based, so check substring presence
+	if !strings.Contains(updates[0], "UPDATE `users` SET") {
+		t.Errorf("update: missing UPDATE clause: %s", updates[0])
+	}
+	if !strings.Contains(updates[0], "WHERE `id` = 1") {
+		t.Errorf("update: missing WHERE clause: %s", updates[0])
+	}
+	if !strings.Contains(updates[0], "`name` = 'charlie'") {
+		t.Errorf("update: missing name set: %s", updates[0])
+	}
+	if !strings.Contains(updates[0], "`age` = 25") {
+		t.Errorf("update: missing age set: %s", updates[0])
+	}
+	if len(deletes) != 0 || len(inserts) != 0 {
+		t.Errorf("expected empty deletes/inserts")
+	}
+}
+
+func TestGenerateChangePreview_EmptyChanges(t *testing.T) {
+	deletes, updates, inserts := GenerateChangePreview("t", connection.ChangeSet{}, mysqlQuote)
+	if len(deletes) != 0 || len(updates) != 0 || len(inserts) != 0 {
+		t.Error("expected all empty for empty changeset")
+	}
+}
+
+func TestFormatLiteral(t *testing.T) {
+	cases := []struct {
+		val      interface{}
+		expected string
+	}{
+		{nil, "NULL"},
+		{"hello", "'hello'"},
+		{"it's a test", "'it\\'s a test'"},
+		{float64(42), "42"},
+		{int64(-1), "-1"},
+		{true, "TRUE"},
+		{false, "FALSE"},
+	}
+	for _, c := range cases {
+		got := formatLiteral(c.val)
+		if got != c.expected {
+			t.Errorf("formatLiteral(%v): got %s, want %s", c.val, got, c.expected)
+		}
+	}
+}
+
+func mysqlQuote(s string) string { return "`" + s + "`" }

internal/db/database.go

@@ -65,6 +65,12 @@ type BatchApplier interface {
 	ApplyChanges(tableName string, changes connection.ChangeSet) error
 }
 
+// ChangePreviewer 是可选的变更预览接口。
+// 驱动可实现此接口提供自定义 SQL 预览格式；若未实现，调用方回退到 GenerateChangePreview。
+type ChangePreviewer interface {
+	PreviewChanges(tableName string, changes connection.ChangeSet) (deletes, updates, inserts []string)
+}
+
 func requireSingleRowAffected(result sql.Result, action string) error {
 	affected, err := result.RowsAffected()
 	if err != nil {