Getting started

This page takes you from download to your first query: install DataKlin, add a PostgreSQL connection, browse the database and run SQL.

System requirements

System	Builds
macOS 13 Ventura or later	Apple silicon (arm64): a .dmg. Intel (x64) Macs: DataKlin 0.2.0 and earlier
Windows 10 or later	x64: an installer (.exe)
Linux	x64: an AppImage, and a .deb for Debian, Ubuntu and related distributions

DataKlin connects to PostgreSQL 14 and later, MySQL 8.0, 8.4 and 9.7, MariaDB 10.11 and 11.8, SQLite, and Apache Cassandra 4.1 and 5.0. This page uses PostgreSQL as the example. Supported databases explains how to connect to each one, and its limits in this release.

Install DataKlin

Get the build for your system from the download section. Each download lists its SHA-256 checksum, which you can compare with the file you downloaded:

# macOS
shasum -a 256 DataKlin-*.dmg
# Linux
sha256sum DataKlin-*.AppImage
# Windows (PowerShell)
Get-FileHash .\DataKlin-*.exe

macOS

1. Open the .dmg. The macOS build needs a Mac with Apple silicon (arm64).
2. Drag DataKlin into Applications.
3. Open DataKlin from Applications. The macOS build is signed and notarized by Apple, so macOS only asks you to confirm opening an app downloaded from the internet. DataKlin 0.2.0 and earlier weren’t notarized: to open one of those, see Opening an unsigned build.

Windows

1. Run the installer (.exe). If Windows SmartScreen stops it, see Opening an unsigned build.
2. Follow the installer. It installs DataKlin for your Windows account and lets you choose the folder.
3. Start DataKlin from the Start menu.

Linux

AppImage: make the file executable, then run it:

chmod +x DataKlin-*.AppImage
./DataKlin-*.AppImage

If the AppImage doesn’t start, your distribution may need FUSE 2, for example the libfuse2 package on Ubuntu (libfuse2t64 from Ubuntu 24.04).

deb: install it with apt, then start DataKlin from your applications menu or with dataklin:

sudo apt install ./DataKlin-*.deb

To save connection passwords encrypted on Linux, DataKlin needs a keyring such as GNOME Keyring or KWallet. See Secret storage on Linux.

Opening an unsigned build

Builds that aren’t signed with an Apple or Microsoft certificate trigger a warning the first time you open them. Check the download’s SHA-256 checksum first (see Install DataKlin), then open it as follows. The checksums of every file are also listed in the release’s SHA256SUMS file, linked from the download section.

macOS (Gatekeeper), DataKlin 0.2.0 and earlier: these builds aren’t notarized by Apple, so macOS can’t verify them and stops the first launch. Later macOS builds are signed and notarized and open without these steps. To open DataKlin 0.2.0 or earlier:

1. Open DataKlin from Applications. When macOS says it can’t verify DataKlin, close the message (Done or OK).
2. Open System Settings → Privacy & Security and scroll to Security. Click Open Anyway next to the message about DataKlin, confirm with your password, then choose Open if macOS asks again. The button is there for about an hour after you try to open DataKlin; if it’s gone, open DataKlin again first.

On macOS 13 Ventura and 14 Sonoma, you can also Control-click (or right-click) DataKlin in Applications and choose Open twice, but from macOS 15 Sequoia this shortcut no longer bypasses the check.

If you prefer the terminal, and you have checked the SHA-256, remove the quarantine flag instead: xattr -dr com.apple.quarantine /Applications/DataKlin.app.

macOS remembers your choice, so you do this once per installed version.

Windows (SmartScreen): when “Windows protected your PC” appears, click More info, then Run anyway.

Linux (AppImage): an AppImage needs no signature, but it must be executable: run chmod +x DataKlin-*.AppImage, or tick “Allow executing file as program” in the file’s properties.

Add a PostgreSQL connection

1. Open the New Connection dialog in any of these ways:
   • In the Connections view of the sidebar, click New Connection (shown while you have none), or right-click the list and choose New Connection.
   • Open the command palette with Ctrl+Shift+P (Cmd+Shift+P on macOS) or F1, and run New Connection.
   • Press Ctrl+K, then Ctrl+N (Cmd+K, then Cmd+N on macOS).
2. Choose PostgreSQL. You can type in the search box to find it.
3. On the General tab, enter the Host, Port (5432 by default), Database (postgres by default), User and Password.
   • Next to the password, choose how long DataKlin keeps it: Save, Until DataKlin quits or Ask every time. See Secret storage for what each option does and how saved passwords are encrypted.
   • If your server uses md5 password authentication instead of SCRAM, tick Allow md5 password authentication.
4. On the Details tab, give the connection a Name. You can also give it a color, an Environment tag and tick Read-only. DataKlin enforces read-only: it refuses writes on that connection. A connection tagged Production always asks before destructive statements. See Read-only and production safety.
5. On the Security tab, check the TLS mode. A new connection to a remote host uses Full verification, and one to localhost isn’t encrypted. See TLS and certificates.
6. Click Test connection to check the details, then Save.

For Amazon Aurora or Amazon RDS, choose Amazon Aurora PostgreSQL or Amazon RDS for PostgreSQL instead: see Amazon Aurora and RDS. SSH tunnels are planned for a later release.

Browse the database

The Database Explorer view in the sidebar shows your connections as a tree.

• Expand a connection to connect to it. If DataKlin doesn’t keep its password, it asks for it.
• Under each schema are Tables, Views, Materialized views, Functions & procedures and Sequences. Expand a table to see its columns, indexes, constraints and triggers.
• Type while the tree has focus to filter it.
• Right-click an object for more: Show Definition opens its DDL, and Copy Name and Copy Qualified Name copy it.
• Press F5 to refresh the selected item, or Shift+F5 to refresh everything.

You can also connect from the Connections view: double-click a connection, or select it and press Enter.

Run and cancel a query

Queries run in a query console, a SQL editor tied to one connection.

• The first time you connect to a connection after starting DataKlin, a console opens for it if it has none. To open another, right-click any connection or object in the Database Explorer and choose New Console Here.
• Type your SQL and click Run, or press Ctrl+Enter (Cmd+Enter on macOS), to run the statement at the cursor, or the selected text. Run all, or Ctrl+Shift+Enter (Cmd+Shift+Enter on macOS), runs every statement in the console.
• To stop a query that’s still running, click Cancel or press Ctrl+. (Cmd+. on macOS). DataKlin asks the server to cancel it and tells you whether it was cancelled or had already finished. If the server hasn’t confirmed the cancel after 10 s, DataKlin offers Close session.

The command palette lists these commands under Console, with their keys.

Read the results

Each statement’s results open in a tab of the results grid, below the console.

• Scroll freely, even through large results: DataKlin loads more rows as you scroll, and the status shows how many are loaded and whether more are available.
• Sort and filter by column, or type in the quick filter in the grid’s toolbar to show the rows where any column contains your text. While the grid has focus, Ctrl+F (Cmd+F on macOS) moves to the quick filter. Sorting and filtering cover the rows fetched so far; when more rows exist, the toolbar says so and offers Fetch all.
• Select cells and press Ctrl+C (Cmd+C on macOS) to copy them. To copy them in another format, run Results: Copy as CSV from the command palette, or Results: Copy as TSV, Results: Copy as JSON or Results: Copy as SQL INSERT.

Find past queries

DataKlin keeps a History of the statements you run: the SQL, the connection, when it ran, how long it took, how many rows it returned and whether it failed. It never stores the results. The history is kept in DataKlin’s local app database on your computer, so it’s still there after a restart.

Open it from the command palette with History: Show, or press Ctrl+Shift+H (Cmd+Shift+H on macOS). It lists the newest statements first. It starts with the connection of the console you’re working in, and you can switch to All connections with its Connection filter.

To clear it, click Clear history… in the History view, or run History: Clear History… from the command palette. When the view shows one connection, you choose that connection or all connections. DataKlin asks before deleting, and clearing can’t be undone. Deleting some history entries, or clearing one connection’s history, can leave fragments of the removed queries in DataKlin’s local database file until it is compacted. Clearing all connections leaves nothing behind.

While DataKlin is running, the history database’s write-ahead log (app.db-wal) grows with each statement you run. It shrinks when you clear or prune history, or at the next start after a crash.

To stop recording, turn off Record query history on the History tab of Settings (Preferences: Open Settings in the command palette). To stop it per connection instead, uncheck the connection under Record history for these connections on the same tab.