diff --git a/Ramitta/Database/PostgreSQL.cs b/Ramitta/Database/PostgreSQL.cs
index ed732d0..262084a 100644
--- a/Ramitta/Database/PostgreSQL.cs
+++ b/Ramitta/Database/PostgreSQL.cs
@@ -29,16 +29,37 @@ namespace Ramitta
             db.Open();
         }
 
-        // 创建表：根据表名和字段定义创建表
+        // 创建表：如果表存在则删除重建
         public void CreateTable(string tableName, Dictionary<string, string> columns)
         {
             // 构建列定义的字符串
             var columnsDefinition = string.Join(", ", columns.Select(c => $"\"{c.Key}\" {MapDataType(c.Value)}"));
-            string createTableQuery = $"CREATE TABLE IF NOT EXISTS \"{tableName}\" ({columnsDefinition});";
 
-            using (var cmd = new NpgsqlCommand(createTableQuery, db))
+            // 删除表（如果存在）然后创建新表
+            string dropQuery = $"DROP TABLE IF EXISTS \"{tableName}\";";
+            string createTableQuery = $"CREATE TABLE \"{tableName}\" ({columnsDefinition});";
+
+            using (var transaction = db.BeginTransaction())
             {
-                cmd.ExecuteNonQuery();
+                try
+                {
+                    using (var dropCmd = new NpgsqlCommand(dropQuery, db))
+                    {
+                        dropCmd.ExecuteNonQuery();
+                    }
+
+                    using (var createCmd = new NpgsqlCommand(createTableQuery, db))
+                    {
+                        createCmd.ExecuteNonQuery();
+                    }
+
+                    transaction.Commit();
+                }
+                catch
+                {
+                    transaction.Rollback();
+                    throw;
+                }
             }
         }
 
@@ -248,6 +269,41 @@ namespace Ramitta
             }
         }
 
+        // 删除表：删除指定名称的表
+        public bool DeleteTable(string tableName)
+        {
+            try
+            {
+                // 验证表名是否为空或空白
+                if (string.IsNullOrWhiteSpace(tableName))
+                {
+                    throw new ArgumentException("表名不能为空", nameof(tableName));
+                }
+
+                // 清理表名，移除可能的特殊字符
+                string cleanTableName = tableName.Trim();
+
+                // 使用参数化查询防止SQL注入
+                string query = $"DROP TABLE IF EXISTS @tableName CASCADE";
+
+                using (var cmd = new NpgsqlCommand(query, db))
+                {
+                    // 使用参数化方式传递表名
+                    cmd.Parameters.AddWithValue("@tableName", cleanTableName);
+
+                    int rowsAffected = cmd.ExecuteNonQuery();
+
+                    // 在PostgreSQL中，DROP TABLE成功执行后ExecuteNonQuery()返回-1
+                    return true;
+                }
+            }
+            catch (Exception ex)
+            {
+                // 记录日志或重新抛出异常
+                throw new InvalidOperationException($"删除表 '{tableName}' 失败: {ex.Message}", ex);
+            }
+        }
+
         // 删除数据：根据条件删除指定表中的记录
         public void DeleteData(string tableName, string condition)
         {
@@ -350,6 +406,224 @@ namespace Ramitta
             return insertedCount;
         }
 
+        #region 权限
+        // 修改用户/角色对表的权限
+        public void GrantTablePermission(string tableName, string userOrRole,
+                                         List<string> permissions, bool withGrantOption = false)
+        {
+            if (db.State != System.Data.ConnectionState.Open)
+            {
+                throw new InvalidOperationException("数据库连接未打开");
+            }
+
+            // 支持的权限类型映射
+            var validPermissions = new Dictionary<string, string>
+    {
+        { "SELECT", "SELECT" },
+        { "INSERT", "INSERT" },
+        { "UPDATE", "UPDATE" },
+        { "DELETE", "DELETE" },
+        { "ALL", "ALL PRIVILEGES" }
+    };
+
+            // 验证权限类型
+            var validPermList = new List<string>();
+            foreach (var perm in permissions)
+            {
+                var upperPerm = perm.ToUpper();
+                if (validPermissions.ContainsKey(upperPerm))
+                {
+                    validPermList.Add(validPermissions[upperPerm]);
+                }
+                else
+                {
+                    throw new ArgumentException($"不支持的权限类型: {perm}");
+                }
+            }
+
+            if (validPermList.Count == 0)
+            {
+                throw new ArgumentException("至少需要指定一个权限");
+            }
+
+            // 构建权限字符串
+            string permissionsStr = string.Join(", ", validPermList);
+
+            // 构建WITH GRANT OPTION部分
+            string grantOption = withGrantOption ? " WITH GRANT OPTION" : "";
+
+            // 构建GRANT语句
+            string grantQuery = $"GRANT {permissionsStr} ON TABLE \"{tableName}\" TO \"{userOrRole}\"{grantOption};";
+
+            using (var cmd = new NpgsqlCommand(grantQuery, db))
+            {
+                cmd.ExecuteNonQuery();
+            }
+        }
+
+        // 撤销用户/角色对表的权限
+        public void RevokeTablePermission(string tableName, string userOrRole,
+                                          List<string> permissions, bool cascade = false)
+        {
+            if (db.State != System.Data.ConnectionState.Open)
+            {
+                throw new InvalidOperationException("数据库连接未打开");
+            }
+
+            // 支持的权限类型映射
+            var validPermissions = new Dictionary<string, string>
+    {
+        { "SELECT", "SELECT" },
+        { "INSERT", "INSERT" },
+        { "UPDATE", "UPDATE" },
+        { "DELETE", "DELETE" },
+        { "ALL", "ALL PRIVILEGES" }
+    };
+
+            // 验证权限类型
+            var validPermList = new List<string>();
+            foreach (var perm in permissions)
+            {
+                var upperPerm = perm.ToUpper();
+                if (validPermissions.ContainsKey(upperPerm))
+                {
+                    validPermList.Add(validPermissions[upperPerm]);
+                }
+                else
+                {
+                    throw new ArgumentException($"不支持的权限类型: {perm}");
+                }
+            }
+
+            if (validPermList.Count == 0)
+            {
+                throw new ArgumentException("至少需要指定一个权限");
+            }
+
+            // 构建权限字符串
+            string permissionsStr = string.Join(", ", validPermList);
+
+            // 构建CASCADE选项
+            string cascadeOption = cascade ? " CASCADE" : "";
+
+            // 构建REVOKE语句
+            string revokeQuery = $"REVOKE {permissionsStr} ON TABLE \"{tableName}\" FROM \"{userOrRole}\"{cascadeOption};";
+
+            using (var cmd = new NpgsqlCommand(revokeQuery, db))
+            {
+                cmd.ExecuteNonQuery();
+            }
+        }
+
+        // 查询表的当前权限
+        public DataTable GetTablePermissions(string tableName)
+        {
+            if (db.State != System.Data.ConnectionState.Open)
+            {
+                throw new InvalidOperationException("数据库连接未打开");
+            }
+
+            // 查询表的权限信息
+            string query = @"
+        SELECT 
+            grantee as 用户角色,
+            string_agg(privilege_type, ', ') as 权限列表,
+            is_grantable as 可授权
+        FROM information_schema.role_table_grants 
+        WHERE table_name = @tableName
+        GROUP BY grantee, is_grantable
+        ORDER BY grantee;";
+
+            using (var cmd = new NpgsqlCommand(query, db))
+            {
+                cmd.Parameters.AddWithValue("tableName", tableName);
+
+                using (var reader = cmd.ExecuteReader())
+                {
+                    DataTable result = new DataTable();
+                    result.Load(reader);
+                    return result;
+                }
+            }
+        }
+
+        // 批量设置权限（可设置多个用户/角色）
+        public void BatchSetPermissions(string tableName, Dictionary<string, List<string>> userPermissions,
+                                        bool withGrantOption = false)
+        {
+            if (db.State != System.Data.ConnectionState.Open)
+            {
+                throw new InvalidOperationException("数据库连接未打开");
+            }
+
+            using (var transaction = db.BeginTransaction())
+            {
+                try
+                {
+                    foreach (var kvp in userPermissions)
+                    {
+                        string userOrRole = kvp.Key;
+                        List<string> permissions = kvp.Value;
+
+                        // 先撤销所有权限，再重新授予
+                        RevokeAllPermissions(tableName, userOrRole);
+
+                        if (permissions.Count > 0)
+                        {
+                            GrantTablePermission(tableName, userOrRole, permissions, withGrantOption);
+                        }
+                    }
+
+                    transaction.Commit();
+                }
+                catch
+                {
+                    transaction.Rollback();
+                    throw;
+                }
+            }
+        }
+
+        // 撤销所有权限
+        private void RevokeAllPermissions(string tableName, string userOrRole)
+        {
+            string revokeQuery = $"REVOKE ALL PRIVILEGES ON TABLE \"{tableName}\" FROM \"{userOrRole}\";";
+
+            using (var cmd = new NpgsqlCommand(revokeQuery, db))
+            {
+                cmd.ExecuteNonQuery();
+            }
+        }
+
+        // 示例：创建用户/角色（如果需要）
+        public void CreateRole(string roleName, string password, bool canLogin = false,
+                               bool isSuperuser = false, bool createDb = false,
+                               bool createRole = false)
+        {
+            if (db.State != System.Data.ConnectionState.Open)
+            {
+                throw new InvalidOperationException("数据库连接未打开");
+            }
+
+            // 构建CREATE ROLE语句
+            List<string> options = new List<string>();
+
+            if (canLogin) options.Add("LOGIN");
+            if (isSuperuser) options.Add("SUPERUSER");
+            if (createDb) options.Add("CREATEDB");
+            if (createRole) options.Add("CREATEROLE");
+
+            string optionsStr = options.Count > 0 ? $" {string.Join(" ", options)}" : "";
+
+            string createRoleQuery = $"CREATE ROLE \"{roleName}\" WITH PASSWORD '{password}'{optionsStr};";
+
+            using (var cmd = new NpgsqlCommand(createRoleQuery, db))
+            {
+                cmd.ExecuteNonQuery();
+            }
+        }
+        #endregion
+
         // 释放资源，关闭数据库连接
         public void Dispose()
         {