PostgreSQL function's input/output as JavaScript nested objects [closed]

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I am looking for a simple/clean way that can be used consistently to automatically input JavaScript nested objects to user-defined PostgreSQL functions and also automatically output to JavaScript nested objects.

Shall I used nested composite types? JSON? other ways? How to parse to/from these types and JavaScript nested objects automatically? Any better thoughts?

Thank you.

Answer 1

JavaScript nested objects can be easily (and I'd say "naturally") represented using JSON. This is "by definition" of what JSON (JavaScript Object Notation) is.

So, in your use-case use JSON

On the JavaScript side:

• To parse the returned values from PostgreSQL (as strings), use JSON.parse().

• To convert JSON to a string that can be included in a SQL statement, use JSON.stringify().

• You can also use some libraries, such as JSON-js, although I've never used it myself.

• See also Safely turning a JSON string into an object.

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In PostgreSQL, on top of using json data type, you might also use jsonb.

It's got a number of advantages (smaller size, indexability, more functions), and a few differences with json (order of fields is not preserved, you can't have {"a":1,"a":2}, and a few other smallish differences that normally don't matter). See Explanation of JSONB introduced by PostgreSQL. Look also at the second answer.

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JSON is not only available in PostgreSQL. Most current databases (MySQL, MS SQL Server, Oracle, SQLite with the JSON1 extension, among others) also support it.