DbCls

DbCls is a terminal-based database client that pairs a built-in SQL editor with visidata for exploring query results. The editor offers syntax highlighting, LM-ranked autocomplete, and customizable keybindings, while visidata turns query output into an interactive, spreadsheet-like view you can filter, sort, pivot, reshape and drill into — all without leaving the terminal. Together they make writing queries and inspecting their results a single, seamless workflow.

Features

• Built-in SQL editor with syntax highlighting and customizable keybindings
• LM-ranked autocomplete for tables, columns, keywords, and functions
• Direct query execution from the editor, results opened straight in visidata
• Powerful interactive data exploration via visidata (filter, sort, pivot, frequency tables, cross-sheet references)
• Support for multiple database engines (MySQL, PostgreSQL, ClickHouse, SQLite, Cassandra / ScyllaDB)
• Unix socket connections with optional auto-SSH tunneling
• Configuration via command line arguments or JSON config file
• Table schema inspection and database / table browsing
• Export results to SQL INSERT statements or any visidata-supported format

Screenshots

SQL Editor

Data Visualization

Installation

pip install dbcls

For Cassandra / ScyllaDB support:

pip install 'dbcls[cassandra]'

Quick Start

Basic usage with command line arguments:

dbcls -H 127.0.0.1 -u user -p mypasswd -E mysql -d mydb mydb.sql

Command Line Options

Option	Description
-H, --host	Database host address
-u, --user	Database username
-p, --password	Database password
-E, --engine	Database engine (mysql, postgres, clickhouse, sqlite3)
-d, --dbname	Database name
-f, --filepath	Database file path (SQLite only)
-P, --port	Port number (optional)
-S, --unix-socket	Path to Unix socket file (optional, overrides host/port)
-c, --config	Path to configuration file
--no-compress	Disable compression for ClickHouse connections
--key-remap	Remap key codes, e.g. "9:353,353:9" to swap Tab and Shift+Tab

Configuration

Using a Config File

You can use a JSON configuration file instead of command line arguments:

dbcls -c config.json mydb.sql

Example config.json:

{
    "host": "127.0.0.1",
    "port": "3306",
    "username": "user",
    "password": "mypasswd",
    "dbname": "mydb",
    "engine": "mysql"
}

Using Bash Configuration

You can also provide configuration directly from a bash script:

#!/bin/bash

CONFIG='{
    "host": "127.0.0.1",
    "port": "3306",
    "username": "user",
    "password": "mypasswd",
    "dbname": "mydb",
    "engine": "mysql"
}'

dbcls -c <(echo "$CONFIG") mydb.sql

Editor Commands

Hotkeys

Hotkey	Action
Alt + 1	Show autocompletion suggestions
Alt + r	Execute query under cursor or selected text
Alt + e	Show database list with table submenu
Alt + t	Show tables list with schema and sample data options
Alt + s	Show list of open VisiData sheets
Ctrl + q	Quit application
Ctrl + s	Save file
Ctrl + h / F1	Show all available hotkeys

Key Remapping

You can remap any key to act as another key using integer key codes.

Via CLI:

dbcls --key-remap "9:353,353:9" mydb.sql

Via environment variable:

export DBCLS_KEY_REMAP="9:353,353:9"
dbcls mydb.sql

The format is a comma-separated list of from:to pairs, where each value is an integer key code. The example above swaps Tab (9) and Shift+Tab (353).

Finding key codes:

Press Ctrl+D inside the editor to enable debug mode — the key code of every pressed key will be shown in the status bar. Press Ctrl+D again to turn it off.

You can also open the help (F1 / Ctrl+H) while debug mode is active to see a full list of all registered keybindings with their codes at the bottom of the help page.

LM-Powered Autocomplete

When dbcls/weights.json is present (see Model Training below), autocomplete suggestions (Alt+1) are ranked by a trained language model that predicts the most likely next SQL token given the current query context.

• Tables, columns, keywords, and functions are sorted by predicted relevance
• When the model expects a column name next, DbCls automatically loads columns from all tables referenced in the current query
• Degrades gracefully: if weights.json is absent or sql_metadata is not installed, autocomplete falls back to alphabetical/prefix ranking

Navigation in Database and Table Listings

When using Alt + e (database list) or Alt + t (table list), use the arrow keys to navigate through the entries and Enter to drill in.

Database List Navigation:

• Select a database and press Enter to proceed to the table list for that database

Table List Navigation:

• Select a table and press Enter to access options:
  • View table schema
  • Show sample data

VisiData Sheets

Press Alt + s to open a list of currently open VisiData sheets. Use the arrow keys to navigate and press Enter to switch to the selected sheet.

To keep sheets open when navigating between them, quit VisiData with Ctrl + q instead of q. Pressing q closes the current sheet, while Ctrl + q exits VisiData entirely while leaving all sheets in memory so they remain accessible via Alt + s.

Data Visualization (visidata)

VisiData is, frankly, the most productive way to look at tabular data in a terminal. It turns a query result into a live, navigable spreadsheet: you can sort and filter on any column, build frequency tables, pivot, melt, join sheets, plot quick histograms, edit cells, follow references between sheets, and export to dozens of formats — all with a few keystrokes and no mouse. DbCls opens every query result directly in visidata, so exploring a database feels less like scrolling through a log and more like poking at a live dataset.

DbCls extends visidata with a handful of DB-aware helpers (cross-sheet references, timestamp conversions, SQL INSERT export, an editable sample-query for each table, and a sheet switcher reachable from the editor via Alt + s).

Hotkeys

Hotkey	Action
zf	Format current cell (JSON indentation, number prettification)
g+	Expand array vertically, similarly to how it's done in expand-col, but by creating new rows rather than columns
gp	Draw a time-series chart from the current sheet's key columns (see Plotting below)
E	Edit the SQL query used to fetch sample data for the current table(in Alt + t page only)

Plotting

Press gp on any VisiData sheet to open an inline terminal chart powered by plotext. The chart is drawn from the sheet's key columns — set them with ! on a column before pressing gp.

Required key column layout (in order):

Position	Type	Role
1st key column	date, datetime, int, or float	X axis (time)
2nd key column (optional)	any	Bucket / series grouping
Last key column	int or float	Y axis (value)

Two-column mode (datetime + value): draws a single line chart.

Three-column mode (datetime + bucket + value): draws one line per unique bucket value. Each series is assigned a number (1, 2, …). Press the corresponding number key to toggle that series on/off.

If rows are selected (s / t), only the selected rows are plotted; otherwise all rows are used.

Example query:

SELECT
    DATE_TRUNC('hour', created_at) AS dt,
    status,
    COUNT(*) AS cnt
FROM orders
GROUP BY 1, 2
ORDER BY 1, 2

Open the result in VisiData, mark dt, status, and cnt as key columns (press ! on each), then press gp.

Exporting Data

DbCls supports exporting data from visidata in multiple formats:

SQL INSERT Export:

1. After executing a query and viewing results in visidata, press either Ctrl+S to save or gY to copy to the clipboard
2. Enter filename with .sql extension (e.g., output.sql)
3. The data will be saved as SQL INSERT statements

The SQL export uses the sheet name as the table name and includes all visible columns. Each row is exported as a separate INSERT statement.

For more visidata hotkeys, visit: https://www.visidata.org/man/

VisiData API Functions

The following functions are available in visidata expressions (press = to create an expression column, then use function_name(...)):

Function	Description
reference(sheet_name, field, value)	Make a reference to another sheet where field == value, on cell open, opens referenced rows in a new sheet
ts_to_dt_utc(ts)	Convert Unix timestamp (str/float/int) to UTC datetime
dt_to_start_of_inteval(dt, interval)	Round a datetime to the start of an interval (interval in seconds)
ts_to_start_of_inteval(ts, interval)	Round a Unix timestamp to the start of an interval (interval in seconds), preserving input type

SQL Commands

Command	Description
.tables	List all tables in current database
.databases	List all available databases
.use <database>	Switch to specified database
.schema <table>	Display schema for specified table

Supported Database Engines

• MySQL
• PostgreSQL
• ClickHouse
• SQLite
• Cassandra / ScyllaDB

Unix Socket Connections

DbCls supports connecting to MySQL and PostgreSQL via a Unix domain socket using the -S / --unix-socket option. When a socket path is provided, it takes precedence over --host and --port.

dbcls -S /tmp/mysql.sock -u user -d mydb -E mysql mydb.sql

Forwarding a Remote Unix Socket Over SSH

If the database server is remote and only accessible via Unix socket, you can forward the socket to your local machine using SSH local socket forwarding:

MySQL:

ssh -L /tmp/mysql.sock:/var/run/mysqld/mysqld.sock -N user@11.22.33.44

PostgreSQL:

ssh -L /tmp/pg.sock:/var/run/postgresql/.s.PGSQL.5432 -N user@11.22.33.44

Then connect using the forwarded local socket:

# MySQL
dbcls -S /tmp/mysql.sock -u user -d mydb -E mysql mydb.sql

# PostgreSQL
dbcls -S /tmp/pg.sock -u user -d mydb -E postgres mydb.sql

Note for PostgreSQL: DbCls automatically creates the required symlink (.s.PGSQL.5432) in the system temp directory so that the aiopg driver can locate the socket correctly. The symlink is recreated on each connection.

Wrapper Script with Auto SSH Tunnel

The script below automatically starts an SSH tunnel, runs dbcls, and kills the tunnel on exit:

MySQL (mysql_ssh.sh):

#!/bin/bash

REMOTE_USER=user
REMOTE_HOST=11.22.33.44
REMOTE_SOCKET=/var/run/mysqld/mysqld.sock
LOCAL_SOCKET=/tmp/dbcls_mysql_$$.sock

ssh -fNM -S /tmp/dbcls_ssh_ctl_$$ \
    -L "$LOCAL_SOCKET:$REMOTE_SOCKET" \
    "$REMOTE_USER@$REMOTE_HOST"

trap "ssh -S /tmp/dbcls_ssh_ctl_$$ -O exit $REMOTE_HOST 2>/dev/null; rm -f $LOCAL_SOCKET" EXIT

dbcls -S "$LOCAL_SOCKET" -u dbuser -d mydb -E mysql "$@"

PostgreSQL (pg_ssh.sh):

#!/bin/bash

REMOTE_USER=user
REMOTE_HOST=11.22.33.44
REMOTE_SOCKET=/var/run/postgresql/.s.PGSQL.5432
LOCAL_SOCKET=/tmp/dbcls_pg_$$.sock

ssh -fNM -S /tmp/dbcls_ssh_ctl_$$ \
    -L "$LOCAL_SOCKET:$REMOTE_SOCKET" \
    "$REMOTE_USER@$REMOTE_HOST"

trap "ssh -S /tmp/dbcls_ssh_ctl_$$ -O exit $REMOTE_HOST 2>/dev/null; rm -f $LOCAL_SOCKET" EXIT

dbcls -S "$LOCAL_SOCKET" -u dbuser -d mydb -E postgres "$@"

How it works:

• ssh -fNM — starts SSH in background (-f) with a master control socket (-M) for easy cleanup
• -S /tmp/dbcls_ssh_ctl_$$ — control socket path (unique per process via $$)
• trap ... EXIT — kills the SSH tunnel and removes the local socket file when the script exits for any reason
• "$@" — passes any extra arguments through to dbcls (e.g. a SQL file path)

Using a Config File with Unix Socket

You can also specify the socket path in a JSON config file:

{
    "username": "user",
    "password": "mypasswd",
    "dbname": "mydb",
    "engine": "mysql",
    "unix_socket": "/tmp/mysql.sock"
}

Password safety

To ensure password safety, I recommend using the project ssh-crypt to encrypt your config file. This way, you can store your password securely and use it with dbcls.

Caveats:

• If you keep the raw password in a shell script, it will be visible to other users on the system.
• Even if you encrypt your password inside a shell script, if you pass it to dbcls via the command line, it will be visible in the process list.

To avoid this, you can use this technique:

#!/bin/bash

ENC_PASS='{V|B;*R$Ep:HtO~*;QAd?yR#b?V9~a34?!!sxqQT%{!x)bNby^5'
PASS_DEC=$(ssh-crypt -d -s "$ENC_PASS")

CONFIG=$(cat <<EOF
{
    "host": "127.0.0.1",
    "username": "user",
    "password": "$PASS_DEC",
    "dbname": "mydb",
    "engine": "mysql"
}
EOF
)

dbcls -c <(echo "$CONFIG") mydb.sql

Model Training

DbCls ships with a train.py script for training or fine-tuning the language model that powers LM-ranked autocomplete. The model is a small MLP trained on SQL corpora; its weights are stored in dbcls/weights.json.

Training from scratch

python train.py train --corpus my_queries.sql

Fine-tuning an existing model

python train.py train --corpus my_queries.sql --finetune
python train.py train --corpus my_queries.sql --finetune --weights custom.json --output custom.json

Inspecting tokenization

Use --debug to print how each SQL statement is tokenized during training:

python train.py train --corpus my_queries.sql --debug

Running inference

python train.py infer --sql "SELECT * FROM"
python train.py infer --sql "SELECT id FROM users WHERE" --top-k 5

Options

Option	Description
--corpus FILE	SQL file for training, one statement per line
--finetune	Load existing weights and continue training
--weights FILE	Weights file to load for fine-tuning (default: dbcls/weights.json)
--output FILE	Where to save trained weights (default: dbcls/weights.json)
--epochs N	Number of training epochs (default: 20)
--lr FLOAT	Learning rate (default: 0.01)
--debug	Print tokenization for each training sentence
--sql TEXT	(infer only) SQL prefix to complete
--top-k N	(infer only) Number of predictions to show (default: 10)

Contributing

Contributions are welcome! Please feel free to submit a Pull Request or submit an issue on GitHub Issues

License

here