feat(db): 添加对达梦数据库的支持

- 在应用程序中新增对达梦数据库（DM）的配置和连接支持
- 实现 SetDmDB 函数以配置达梦数据库连接
- 更新数据库操作逻辑，支持达梦特有的 SQL 语法和功能
- 在相关文件中添加达梦数据库的处理逻辑，包括表创建、数据插入和查询
- 更新 go.mod 和 go.sum 文件以引入达梦数据库驱动
- 增强文档，详细说明达梦数据库的配置和使用方法

db/backup.go

@@ -14,13 +14,18 @@ func (that *HoTimeDB) backupSave(path string, tt string, code int) {
 	fd, _ := os.OpenFile(path, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0644)
 	defer fd.Close()
 
+	q := "`"
+	if that.Dialect != nil {
+		q = that.Dialect.QuoteChar()
+	}
+
 	str := "\r\n"
 	if code == 0 || code == 2 {
 		str += that.backupDdl(tt)
 	}
 
 	if code == 0 || code == 1 {
-		str += "insert  into `" + tt + "`\r\n\r\n("
+		str += "insert  into " + q + tt + q + "\r\n\r\n("
 		str += that.backupCol(tt)
 	}
 
@@ -29,16 +34,69 @@ func (that *HoTimeDB) backupSave(path string, tt string, code int) {
 
 // backupDdl 备份表结构（DDL）
 func (that *HoTimeDB) backupDdl(tt string) string {
-	data := that.Query("show create table " + tt)
-	if len(data) == 0 {
+	switch that.Type {
+	case "dm", "dameng":
+		return that.backupDdlDM(tt)
+	default:
+		data := that.Query("show create table " + tt)
+		if len(data) == 0 {
+			return ""
+		}
+		return ObjToStr(data[0]["Create Table"]) + ";\r\n\r\n"
+	}
+}
+
+// backupDdlDM 达梦数据库 DDL 导出
+func (that *HoTimeDB) backupDdlDM(tt string) string {
+	cols := that.Query(`SELECT COLUMN_NAME, DATA_TYPE, DATA_LENGTH, DATA_PRECISION, DATA_SCALE, NULLABLE, DATA_DEFAULT FROM USER_TAB_COLUMNS WHERE TABLE_NAME='` + tt + `' ORDER BY COLUMN_ID`)
+	if len(cols) == 0 {
 		return ""
 	}
 
-	return ObjToStr(data[0]["Create Table"]) + ";\r\n\r\n"
+	ddl := "CREATE TABLE \"" + tt + "\" (\r\n"
+	for i, col := range cols {
+		name := col.GetString("COLUMN_NAME")
+		dtype := col.GetString("DATA_TYPE")
+		nullable := col.GetString("NULLABLE")
+		defVal := col.GetString("DATA_DEFAULT")
+
+		colDef := "  \"" + name + "\" " + dtype
+		prec := col.GetInt("DATA_PRECISION")
+		scale := col.GetInt("DATA_SCALE")
+		length := col.GetInt("DATA_LENGTH")
+		if prec > 0 {
+			colDef += "(" + ObjToStr(prec)
+			if scale > 0 {
+				colDef += "," + ObjToStr(scale)
+			}
+			colDef += ")"
+		} else if length > 0 && (strings.Contains(strings.ToUpper(dtype), "CHAR") || strings.Contains(strings.ToUpper(dtype), "BINARY")) {
+			colDef += "(" + ObjToStr(length) + ")"
+		}
+
+		if nullable == "N" {
+			colDef += " NOT NULL"
+		}
+		if defVal != "" {
+			colDef += " DEFAULT " + strings.TrimSpace(defVal)
+		}
+
+		if i < len(cols)-1 {
+			colDef += ","
+		}
+		ddl += colDef + "\r\n"
+	}
+	ddl += ");\r\n\r\n"
+	return ddl
 }
 
 // backupCol 备份表数据
 func (that *HoTimeDB) backupCol(tt string) string {
+	q := "`"
+	if that.Dialect != nil {
+		q = that.Dialect.QuoteChar()
+	}
+
 	str := ""
 	data := that.Select(tt, "*")
 
@@ -54,9 +112,9 @@ func (that *HoTimeDB) backupCol(tt string) string {
 
 	for k := range data[0] {
 		if tempLthData == lthCol-1 {
-			str += "`" + k + "`) "
+			str += q + k + q + ") "
 		} else {
-			str += "`" + k + "`,"
+			str += q + k + q + ","
 		}
 		col[tempLthData] = k
 		tempLthData++