Importing Data
Zequel can import data from CSV and JSON files into an existing database table. The import workflow includes a file preview, column mapping, and type conversion.
Starting an Import
To begin importing data:
- Right-click a table name in the sidebar.
- Select "Import Data".
- Choose the file format: CSV or JSON.
- A native file dialog opens. Select the file you want to import.
After selecting a file, Zequel parses it and displays a preview of the data.
Import Preview
The import preview shows:
- Detected columns -- Column names inferred from the file (CSV headers or JSON keys).
- Sample values -- A few sample values from each column to help verify the data looks correct.
- Detected types -- Zequel analyzes sample values to suggest a data type for each column (e.g., INTEGER, TEXT, BOOLEAN).
- Total rows -- The total number of rows detected in the file.
The preview displays up to 100 rows. The full file is imported when you execute the import.
Adjusting Parse Options
If the preview does not look right, you can adjust parse options and re-parse the file:
- Has headers -- Toggle whether the first row of a CSV file is treated as column headers. When disabled, columns are named generically (e.g.,
column_1,column_2). - Delimiter -- For CSV files, change the delimiter character (comma, semicolon, tab, or a custom character).
The preview updates automatically after changing these options.
Column Mapping
Before executing the import, map each source column from the file to a target column in the database table:
| Setting | Description |
|---|---|
| Source Column | The column name from the imported file. |
| Target Column | The column in the database table where the data will be inserted. |
| Target Type | The database column type, used for automatic type conversion during import. |
Zequel fetches the target table's column definitions to populate the mapping dropdowns. Columns that do not have a mapping are skipped during import.
Type Conversion
Values are automatically converted based on the target column type:
- INTEGER, BIGINT, SMALLINT -- Parsed as integers. Non-numeric values become
NULL. - DECIMAL, FLOAT, DOUBLE, REAL, NUMERIC -- Parsed as floating-point numbers.
- BOOLEAN -- Recognizes
true,1, andyesas true; everything else is false. - JSON, JSONB -- String values are parsed as JSON if valid.
- TEXT, VARCHAR, and other string types -- Values are kept as strings.
Executing the Import
After configuring column mappings, click "Import" to start the import. Zequel inserts rows one at a time, in batches. During the import:
- A progress indicator shows how many rows have been processed.
- If Truncate table is enabled, all existing rows in the target table are deleted before inserting new data.
- Errors on individual rows are collected and reported at the end without stopping the entire import.
When the import completes, a summary shows the number of successfully inserted rows and any errors encountered.
Limitations
- Import supports CSV and JSON formats. SQL and Excel file import is not supported through the Import Dialog. To import from a SQL file, use the Backup and Restore feature.
- Rows are inserted individually, which may be slow for very large files. For bulk loading, consider using your database's native import tools.
- Error messages are capped at 100 entries in the summary to avoid overwhelming the interface.
Next Steps
- Exporting Data -- Export table data or query results to a file.
- Supported Formats -- Learn about the details of each file format.
- Backup and Restore -- Import full database backups from SQL files.