If you want to convert JSON to SQL there’s no concrete or straightforward way of doing things. Conversion is usually tricky because JSON and SQL are written using different structures.

Realistically, you have only two options: use a conversion tool like SQLizer or write some code and build yourself a script to do it for you. We’ll cover both methods in this blog.

You can roll up your sleeves and write some code. Build a custom script to handle the conversion. But let’s start with the easy way using SQLizer: SQLizer.

Step 1: Drag and drop your JSON file into SQLizer

Drag and drop a JSON file to convert to SQL

Step 2: Select your options

Choose your JSON to SQL conversion options

Step 3: Hit convert

You’re nearly done - your SQL file will be ready in a few seconds. It’s really that easy.

Here’s a video showing the exact steps to convert JSON to SQL in 30 seconds:

SQLizer is definitely the easier method of converting JSON files to SQL databases. But as promised, here’s a breakdown of building yourself a script.

How to convert JSON to SQL with your own script

Converting JSON to SQL can be a bit tricky, but let’s dive into the details. While I won’t provide an exact step-by-step script, I’ll outline some key considerations if you decide to write your own conversion script in Python:

  1. Data Structure Mapping: JSON and SQL have different structures. When writing your script, ensure that you map JSON objects and arrays to corresponding SQL tables and columns.
  2. Data Types: Pay attention to data types. JSON values (like strings, numbers, and booleans) need to be mapped to appropriate SQL data types (e.g., VARCHAR, INT, DECIMAL).
  3. Nested Data: Handle nested JSON structures. If your JSON contains nested objects or arrays, decide how to flatten or normalize them in your SQL schema.
  4. Null Values: Consider how you’ll handle null values. JSON allows null, while SQL has its own NULL representation. Escape Characters: Be cautious with special characters and escape sequences. Ensure proper escaping to prevent SQL injection.

You can convert JSON to SQL by writing a script in most programming languages. The example below uses Python. Here’s what the Python script looks like:

import json

with open('strings.json') as json_data:    d = json.load(json_data)    print(d)

It’s not that simple

“Is that all?” I hear you think. Well, it isn’t as simple as writing and deploying this script.

JSON files are built in a hierarchy with trees of “objects” within the data. Herein lies the problem: SQL is written in a “flat” structure so you need to somehow turn the hierarchical JSON data into a “flat” table with columns and rows.

The most reliable method to convert JSON to SQL is to “flatten” the JSON data - this is what SQLizer does.

Let’s look at some examples.

JSON to SQL example 1

Here’s some JSON code we want to convert to SQL:

{    "ListOne": [        {            "foo": 1,            "bar": 2        },        {            "foo": 3,            "bar": 4        }    ],    "ValTwo": "baz",    "ValThree": "fizz"}

After flattening the JSON and converting to SQL, you end up with the following:

CREATE TABLE object_with_list_of_objects (    `ListOne_foo` INT,    `ListOne_bar` INT,    `ValTwo` VARCHAR(3) CHARACTER SET utf8,    `ValThree` VARCHAR(4) CHARACTER SET utf8);INSERT INTO object_with_list_of_objects VALUES (1,2,NULL,NULL);INSERT INTO object_with_list_of_objects VALUES (3,4,'baz','fizz');

In the above example, “ListOne” contains two objects, each with the two values of “foo” and “bar”. Both “foo” and “bar” get their own rows in our database table.

But this isn’t the only way of converting JSON to SQL. If we switch the order of the JSON around we get different SQL.

JSON to SQL example 2

Here’s the reversed JSON:

{    "ValOne": "baz",    "ValTwo": "fizz",    "ListThree": [        {            "foo": 1,            "bar": 2        },        {            "foo": 3,            "bar": 4        }    ]}

And here’s the resulting SQL after flattening the reversed JSON:

CREATE TABLE object_with_list_of_objects (    `ValOne` VARCHAR(3) CHARACTER SET utf8,    `ValTwo` VARCHAR(4) CHARACTER SET utf8,    `ListThree_foo` INT,    `ListThree_bar` INT);INSERT INTO object_with_list_of_objects VALUES ('baz','fizz',1,2);INSERT INTO object_with_list_of_objects VALUES ('baz','fizz',3,4);

You’ll notice that “ValOne” and “ValTwo” appear at the top of this SQL and that their values have been “filled down” all the rows. The SQL is reversed.

No ‘right’ way

Converting JSON to SQL isn’t a one-size-fits-all process, and there’s no definitive “right” or “wrong” way to do it. Each approach has its trade-offs, and the choice depends on factors like your specific use case, available tools, and programming language preferences.

Not to mention each programming language has different ways of “flattening” or converting JSON. Just check out this StackOverflow post to see how you can write a script in PHP. You can see how it’s a different process.

A pitfall to avoid: losing data

Another issue to think about is losing the meaning of data from JSON when converting over to SQL. Because the structure changes and there’s no single way of doing this, it’s likely that some meaning from the JSON gets lost in the SQL file somewhere.

SQLizer is built to never lose value during conversion. It took lots of testing and iteration but SQLizer ensures no value is ever lost and that everything is always in the SQL file.

DIY or use SQLizer

As you can see it’s neither easy nor simple to convert JSON to SQL with DIY methods. If you really want to do it yourself, taking the knowledge above, you can find great tips on StackOverflow.

If you’d rather save hours of your time then upload your file to SQLizer and wait about 30 seconds while it converts your JSON file to a SQL database.

Spend less time converting, more time doing actual work. Convert your JSON file now.

🖤 SQLizer team.

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