Schema browser and history

中文 · Docs

The sidebar has two tabs: Schema and History (表结构 and 查询历史 in Chinese). Beside them, the collapse button (or ⌘B) hides the sidebar; the button at the left of the title bar, or ⌘B again, brings it back. Whether it is hidden is remembered.

The schema tree

The tree shows, from the top:

• Local files — the data files you have registered, each named by its view, with its row count. The file name appears beside the view name only when the two differ (sales_2 from sales.csv), and the folder when two files share a view name; hover a row for the full path. Its children are the view's columns.
• Apps / Dashboards — the analysis apps and .dash dashboards you have opened recently, sorted by name so a row stays put when you click it. Click one to reopen it as a tab, the way you would a file; the × on hover takes it off the list, leaving its files and any open tab alone. An entry whose path no longer exists is dropped from the list.
• S3 — present once S3 is configured. Loads lazily.
• Each database, then its schemas, then tables and views, then columns.

Tables show an estimated row count; views show none. Column rows show the DuckDB data type. The system database and the information_schema, pg_catalog, and system schemas are hidden.

Refresh schema reloads the catalog and re-attaches the registered files.

Generating a SELECT

Three things fill the active editor when clicked:

Click	Generated SQL
A table's play button	SELECT * FROM db.schema.table LIMIT 100;
A table's column name	SELECT col FROM db.schema.table LIMIT 100;
An S3 object that is a data file	SELECT * FROM 's3://bucket/key' LIMIT 100;

Names are fully qualified as database.schema.table, and double-quoted only when they are not plain identifiers.

Note that all three replace the entire buffer of the active tab — they do not insert at the cursor. The same is true of clicking a history entry. Save anything you care about before clicking around.

Altering a column type

A column row offers a type action (not available on view columns, so attached CSV and Parquet columns cannot be retyped). It opens a free-text dialog pre-filled with the current type and runs:

ALTER TABLE db.schema.table ALTER COLUMN "col" SET DATA TYPE <what you typed>;

There is no picker and no validation list — any DuckDB type string works, including parameterised ones like DECIMAL(10,2). An invalid type comes back as an error notification. Success reloads the catalog.

Renaming and dropping columns, and editing column comments, are not available.

Removing a registered file

The × on a file row asks for confirmation, then drops the view and forgets the registration. The file on disk is not touched.

Query history

Every run is recorded — successes and failures alike — with a local-time timestamp, duration in milliseconds, row count (or affected-row count for DML), and the error text if it failed. Failed entries are shown in red with a Failed tag.

The list shows the newest 200 entries. Clicking a row refills the active editor with that SQL and focuses it, replacing whatever was there.

There is no retention policy and no pruning: the history table grows without bound, and the UI simply shows the most recent 200. There is also no search, no filter, no export, and no way to delete an entry from the interface.

History is stored in DuckLocal's own database file, not in the database you have open, so it survives switching databases and losing your workspace. See Settings and app data for where it lives.