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

cache/cache_db.go

@@ -155,6 +155,11 @@ func (that *CacheDb) tableExists(tableName string) bool {
 	case "postgres":
 		res := that.Db.Query(`SELECT tablename FROM pg_tables WHERE schemaname='public' AND tablename='` + tableName + `'`)
 		return len(res) != 0
+
+	case "dm", "dameng":
+		// 双引号创建的表名保留原始大小写，不能 ToUpper
+		res := that.Db.Query(`SELECT TABLE_NAME FROM USER_TABLES WHERE TABLE_NAME='` + tableName + `'`)
+		return len(res) != 0
 	}
 
 	return false
@@ -201,7 +206,21 @@ func (that *CacheDb) createMainTable(dbType, tableName string) {
 			"modify_time" TIMESTAMP
 		)`
 		that.Db.Exec(createSQL)
-		// 创建索引
+		that.Db.Exec(`CREATE INDEX "idx_` + tableName + `_end_time" ON "` + tableName + `" ("end_time")`)
+		return
+
+	case "dm", "dameng":
+		createSQL = `CREATE TABLE "` + tableName + `" (
+			"id" INT IDENTITY(1,1) PRIMARY KEY,
+			"key" VARCHAR(64) NOT NULL,
+			"value" TEXT,
+			"end_time" TIMESTAMP,
+			"state" INT DEFAULT 0,
+			"create_time" TIMESTAMP,
+			"modify_time" TIMESTAMP,
+			CONSTRAINT "uk_` + tableName + `_key" UNIQUE ("key")
+		)`
+		that.Db.Exec(createSQL)
 		that.Db.Exec(`CREATE INDEX "idx_` + tableName + `_end_time" ON "` + tableName + `" ("end_time")`)
 		return
 	}
@@ -252,7 +271,21 @@ func (that *CacheDb) createHistoryTable(dbType, tableName string) {
 			"modify_time" TIMESTAMP
 		)`
 		that.Db.Exec(createSQL)
-		// 创建索引
+		that.Db.Exec(`CREATE INDEX "idx_` + tableName + `_cache_id" ON "` + tableName + `" ("hotime_cache_id")`)
+		return
+
+	case "dm", "dameng":
+		createSQL = `CREATE TABLE "` + tableName + `" (
+			"id" INT IDENTITY(1,1) PRIMARY KEY,
+			"hotime_cache_id" INT,
+			"key" VARCHAR(64),
+			"value" TEXT,
+			"end_time" TIMESTAMP,
+			"state" INT DEFAULT 0,
+			"create_time" TIMESTAMP,
+			"modify_time" TIMESTAMP
+		)`
+		that.Db.Exec(createSQL)
 		that.Db.Exec(`CREATE INDEX "idx_` + tableName + `_cache_id" ON "` + tableName + `" ("hotime_cache_id")`)
 		return
 	}
@@ -291,9 +324,19 @@ func (that *CacheDb) migrateFromCached(dbType, oldTableName, newTableName string
 			`INNER JOIN (SELECT "key", MAX(id) as max_id FROM "` + oldTableName + `" GROUP BY "key") m ` +
 			`ON c.id = m.max_id ` +
 			`ON CONFLICT ("key") DO NOTHING`
+
+	case "dm", "dameng":
+		migrateSQL = `MERGE INTO "` + newTableName + `" t USING (` +
+			`SELECT c."key", c."value", DATEADD(SECOND, c."endtime", TIMESTAMP '1970-01-01 00:00:00') AS "end_time", ` +
+			`DATEADD(SECOND, c."time" / 1000000000, TIMESTAMP '1970-01-01 00:00:00') AS "create_time" ` +
+			`FROM "` + oldTableName + `" c ` +
+			`INNER JOIN (SELECT "key", MAX("id") AS max_id FROM "` + oldTableName + `" GROUP BY "key") m ` +
+			`ON c."id" = m.max_id` +
+			`) src ON (t."key" = src."key") ` +
+			`WHEN NOT MATCHED THEN INSERT ("key", "value", "end_time", "state", "create_time", "modify_time") ` +
+			`VALUES (src."key", src."value", src."end_time", 0, src."create_time", src."create_time")`
 	}
 
-	// 执行迁移，不删除老表（由人工确认后删除，更安全）
 	that.Db.Exec(migrateSQL)
 }
 
@@ -455,6 +498,14 @@ func (that *CacheDb) set(key string, value interface{}, endTime time.Time) {
 			`ON CONFLICT ("key") DO UPDATE SET "value"=EXCLUDED."value", "end_time"=EXCLUDED."end_time", "modify_time"=EXCLUDED."modify_time"`
 		that.Db.Exec(upsertSQL, key, string(bte), endTimeStr, nowTime, nowTime)
 
+	case "dm", "dameng":
+		upsertSQL := `MERGE INTO "` + tableName + `" t USING (SELECT ? AS "key", ? AS "value", ? AS "end_time", ? AS "create_time", ? AS "modify_time") src ` +
+			`ON (t."key" = src."key") ` +
+			`WHEN MATCHED THEN UPDATE SET "value"=src."value", "end_time"=src."end_time", "modify_time"=src."modify_time" ` +
+			`WHEN NOT MATCHED THEN INSERT ("key", "value", "end_time", "state", "create_time", "modify_time") ` +
+			`VALUES (src."key", src."value", src."end_time", 0, src."create_time", src."modify_time")`
+		that.Db.Exec(upsertSQL, key, string(bte), endTimeStr, nowTime, nowTime)
+
 	default:
 		// 兼容其他数据库：使用 Update + Insert
 		num := that.Db.Update(tableName, Map{