Convert DDB to CSV
Upload a .duckdb or .ddb file and get back a CSV file. Types are preserved rather than flattened to text. Free, no registration, up to 10MB.
Click to upload or drag and drop
CSV, Excel, SQLite, SQL, DBF (max 10 MB)
How your data is typed in CSV
Generated from the converter's own CSV type mapping — this is what it actually emits, not an example.
| Your data | CSV type |
|---|---|
| Whole number | text (CSV has no types) |
| Decimal (money) | text (CSV has no types) |
| Floating point | text (CSV has no types) |
| True / false | text (CSV has no types) |
| Date | text (CSV has no types) |
| Date and time | text (CSV has no types) |
| Short text | text (CSV has no types) |
| Long text | text (CSV has no types) |
| Binary data | text (CSV has no types) |
Working from a .ddb file
.ddb is the short form of the DuckDB extension, and DuckDB itself does not care what you call a database file. The uploader does: it routes on the extension alone, so the name you saved under decides which reader ever sees the file.
- →.ddb and .duckdb both reach the DuckDB reader and are read identically. Nothing inside the file records which of the two you chose - the storage version is in the header, the name is not.
- →One file is this format's whole promise, so make sure it really is one file before you send it: closing the DuckDB CLI cleanly, or running CHECKPOINT first, folds the write-ahead log back into the database itself.
- →A file with no extension at all, which DuckDB is perfectly happy to create, is not recognised as anything and is refused before it is read.
The shape of the CSV files you get
CSV is where the type information stops, so what is left to describe is the file itself: how a row is terminated, which fields are quoted, and how a value that used to have a type is spelled out as characters.
- →Rows end with a carriage return and a line feed, the RFC 4180 ending, while a newline inside a quoted field stays the single character it always was. The encoding is UTF-8 with no byte-order mark in front of it.
- →Quotes go on only where they are needed - a field holding a comma, a double quote or a newline - and a quote inside a field is doubled rather than escaped with a backslash. Every other field is written bare.
- →Decimal values are written digit for digit and never through a floating-point number, so a money column that was exact in the source is still exact in the file. Booleans are written lower case, as true and false, which is the spelling this converter's own reader takes back as a boolean.
Reading DDB
- →Types, primary keys and NOT NULL constraints are read from the database.
- →The file is opened read-only, so your upload is never modified or upgraded in place.
Writing CSV
- →One file per table, with a header row.
- →NULL is written as an empty field, never the word "None".
- →Binary data is written as hex, which is reversible.
What you get
A ZIP containing <table>.csv. If anything about your data needed a judgement call, a _warnings.txt explains it.
Questions
- Is converting DDB to CSV free?
- Yes. Files up to 10MB convert free with no account. There is a limit of five conversions per day per IP address.
- Will my DDB data keep its types in CSV?
- Yes — that is the point. Whole numbers, decimals, dates and booleans are mapped to real CSV types rather than everything becoming text. The mapping table above shows exactly what you get.
- Do you store my file?
- No. The file is written to a temporary directory, converted, and the directory is deleted as soon as your download has been sent.