Convert DDB to psql
Upload a .duckdb or .ddb file and get back a psql SQL script you can load straight into your database. 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 psql
Generated from the converter's own psql type mapping — this is what it actually emits, not an example.
| Your data | psql type |
|---|---|
| Whole number | BIGINT |
| Decimal (money) | NUMERIC(10,2) |
| Floating point | DOUBLE PRECISION |
| True / false | BOOLEAN |
| Date | DATE |
| Date and time | TIMESTAMP |
| Short text | TEXT |
| Long text | TEXT |
| Binary data | BYTEA |
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.
Running the script through psql
psql is PostgreSQL's command-line client rather than the database itself, and the script is written to be fed straight into it. Everything here is about the tool you run, not about the server you run it against.
- →From inside a session already open, \i dump.sql runs the file without leaving the prompt. The script contains no backslash meta-commands of its own, so nothing in it can collide with yours.
- →There is no BEGIN and no COMMIT anywhere in the file. Statements commit as they go, so a failure halfway leaves the tables already created: pass -1 to wrap the whole load in a single transaction, or -v ON_ERROR_STOP=1 to stop at the first error instead of carrying on past it.
- →The script switches standard_conforming_strings on itself instead of trusting the server default, so it behaves identically against a session that has been moved off it.
- →It sets client_encoding to UTF8 for the same reason. The file is written as UTF-8 with nothing to announce that, and psql would otherwise decode it using whatever the client locale says.
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 psql
- →Backslashes are left alone, because PostgreSQL treats them as ordinary characters — doubling them would corrupt every Windows path.
- →Auto-increment columns become GENERATED BY DEFAULT AS IDENTITY.
- →Binary data is written as bytea, and identifiers respect the 63-character limit.
What you get
A ZIP containing dump.sql, plus a README with the exact command to load it. If anything about your data needed a judgement call, a _warnings.txt explains it.
Load this dump into PostgreSQL: psql -U USER -d DATABASE -f dump.sql Create the database first if it does not exist: createdb -U USER DATABASE
Questions
- Is converting DDB to psql 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 psql?
- Yes — that is the point. Whole numbers, decimals, dates and booleans are mapped to real psql 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.