DB RelationalAlgebra vs MaidKit

A native iPad and iPhone app that converts a SQL query typed, pasted, or imported from a .sql file into relational algebra, tuple relational calculus and domain relational calculus. Each notation gets a step by step derivation, a final oneline formula, and an interactive diagram an operator tree for the algebra, a quantifier scope tree for the calculus and a fourth view stacks all three against the same query. Whatever SQL asks for that a notation cannot express exactly is reported rather than quietly approximated.

MaidKit is a non-intrusive SSH server manager for Linux administrators who want full control without installing agent software on their servers. Everything runs over a standard SSH connection — no daemons, no agents, no added attack surface. Monitor at a glance • Dashboard with live status, load, memory, and uptime for every server • Real-time charts for CPU, memory, network, and disk activity Work in a real terminal • Full SSH terminal with split panes, draggable tabs, and a command palette • Two renderers to choose from: fast native VT rendering or classic xterm Manage files like a pro • Dual-pane SFTP browser with drag-and-drop transfers • Built-in editor for quick remote edits Run your daily operations • Processes: inspect and terminate running processes • Services: manage systemd units (start, stop, enable, disable) • Web servers: configure nginx and Caddy • Scheduled tasks: edit crontabs • Packages: manage apt, dnf, and more • Firewall: manage UFW, firewalld, nftables, and iptables • Port forwarding: local and remote tunnels Containers • Manage Docker and Podman containers: start, stop, restart, pause, and remove • Compose project grouping and image management Projects & snippets • Organize compose stacks, web servers, and containers into deployment projects; import and export as TOML • Save reusable shell scripts and run them on one or many servers with streaming output Security first • AES-GCM 256-bit encrypted credential vault with PBKDF2 key derivation (310,000 iterations) • Biometric unlock support • Encrypted backup archives Built with a calm, desktop-native interface. Available in English and 简体中文.