Convert JSON to MariaDB

Upload a .json or .ndjson file and get back a MariaDB 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 MariaDB

Generated from the converter's own MariaDB type mapping — this is what it actually emits, not an example.

Your dataMariaDB type
Whole numberBIGINT
Decimal (money)DECIMAL(10,2)
Floating pointDOUBLE
True / falseTINYINT(1)
DateDATE
Date and timeDATETIME
Short textVARCHAR(255)
Long textLONGTEXT
Binary dataLONGBLOB

Working from a .json file

A .json file can be almost any shape, and only a few of those shapes are a table. What the reader accepts, and what it does with the rest, is the thing worth knowing before you upload one.

  • A wrapper is unwrapped only when the object has exactly one key and that key holds a list of objects. {"meta": {...}, "data": [...]} has two keys, so it is read as a single row instead.
  • An array of strings, or an array of arrays, is refused with "Expected a JSON array of objects" - there are no column names in it to build a table from.
  • Columns are the union of the keys seen in the first 10,000 records, in the order they first appear. A key that shows up only after that is not part of the table.

What MariaDB gets, and how it differs

MariaDB and MySQL are close enough here that one dialect serves both, and picking MariaDB does not select a different code path: the script is byte for byte the one a MySQL conversion produces. The differences worth flagging are in what you do with it.

  • The README packed beside the script names both engines in its load command, because the invocation is the same either way - the file is piped into a client rather than executed by the server.
  • The CREATE DATABASE line in that README asks for utf8mb4_unicode_ci and not for utf8mb4_0900_ai_ci, which is MySQL 8's default. MariaDB has never implemented the 0900 collations, and unicode_ci is the one both engines have.
  • Date-and-time columns are declared DATETIME rather than TIMESTAMP, so what loads is the wall-clock value the source held. No session time zone is applied on the way in, and none is applied when you read it back out.

Reading JSON

  • JSON types are trusted: 1 and "1" stay different things.
  • Numbers with a decimal point are read as exact decimals rather than floats.
  • Both an array of objects and newline-delimited JSON work, and a wrapped array like {"data": [...]} is unwrapped automatically.
  • Nested objects are kept as JSON rather than flattened into invented column names.

Writing MariaDB

  • Tables are created as InnoDB with utf8mb4, so emoji and CJK text survive the load.
  • Backslashes are escaped, because MySQL treats them as escape characters by default.
  • Text columns of unknown length become TEXT rather than a guessed VARCHAR that could truncate your data.
  • Inserts are batched, and identifiers are capped at MySQL’s 64-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 MySQL or MariaDB:

  mysql -u USER -p DATABASE < dump.sql

Create the database first if it does not exist:

  mysql -u USER -p -e "CREATE DATABASE DATABASE CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;"

Questions

Is converting JSON to MariaDB 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 JSON data keep its types in MariaDB?
Yes — that is the point. Whole numbers, decimals, dates and booleans are mapped to real MariaDB 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.

This conversion, under other names

Convert JSON to something else

Convert something else to MariaDB