File uploads (CSV, Excel, Parquet, JSON)

Upload static files (CSV, Excel, Parquet, JSON)

In addition to live database connectors, the DQC Platform lets you upload static files directly. Each upload becomes its own connector with one table — useful for one-off checks, sample data or data feeds you receive as files.

Add a file connector

Go to the Connectors > Data sources screen
Pick the tile that matches your file type: CSV, Excel, Parquet or JSON
Enter a Table Name, select the file to upload, and submit

Table names may only contain letters, digits, spaces, dashes and underscores. All uploads are stored encrypted on the platform's storage backend.

Supported file types

Type	Extensions	Notes
CSV	`.csv`	Encoding is auto-detected and converted to UTF-8. Delimiter can be auto-detected or selected manually (see below).
Excel	`.xlsx`	Only the first sheet is imported. Legacy `.xls` files are not supported — re-save them as .xlsx.
Parquet	`.parquet`	Imported as-is. Schema and data types are preserved.
JSON	`.json`	A flat list of objects works best. DQC flattens shallow `{field: {value: X}}` wrappers automatically; deeply nested structures should be flattened beforehand.

Maximum file size: 100 MB by default.

CSV — delimiter handling

When uploading a CSV file you choose a delimiter:

automatic — DQC sniffs the delimiter from the first lines (recommended for most files)
comma (,), semicolon (;), colon (:), pipe (|), tilde (~), caret (^)
custom — enter any single character if your file uses a different separator

Each CSV table within a connector remembers its own delimiter, so you can mix files with different separators in the same workspace.

Updating an existing file table

Open the file connector, choose the table you want to refresh and upload a new file. DQC replaces the table contents atomically — checks and rules already attached to the table remain valid as long as column names match.

Connect and assign permissions

To control who can view and use uploaded files inside DQC, see Data source access permissions.

Troubleshooting

When DQC cannot connect to file uploads or load its tables, it shows the reason with a short fix and links to this section. Look up the beginning of the message:

Message in DQC	Likely cause	Fix
`Unsupported file extension: …`	The file type is not supported	Upload CSV, Excel (`.xlsx`), JSON or Parquet
`The legacy .xls format is not supported. …`	The Excel file is in the old `.xls` format	Save it as `.xlsx` and upload it again
`Name can only include letters, numbers, spaces, dashes and underscores. …`	The table name contains other characters	Rename the table
`Data table name '…' already exists: …`	A table or file with this name exists	Choose another name, or update the existing table (see Updating an existing file table)
`We encountered an error while processing your request. …`	The file cannot be read: a CSV or JSON file that is not UTF-8, invalid JSON, a corrupt Parquet file or a password-protected Excel file	Save the file as UTF-8, validate it, or remove the password protection, then upload it again
`Request timed out`	The file is too large to process in one request	Split the file

Rows missing after a CSV upload: rows that do not match the detected format are skipped. Set the delimiter explicitly (see the CSV delimiter section) and compare the row count.
Only the first sheet of an Excel file is imported.
Still stuck? Write to support@dqc.ai with the connector name, the time of the attempt and the full message.