https://github.com/rluba/jai-postgres

Mimimal Postgresql client for Jai
https://github.com/rluba/jai-postgres

Last synced: 2 months ago
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Mimimal Postgresql client for Jai

• Host: GitHub
• URL: https://github.com/rluba/jai-postgres
• Owner: rluba
• License: mit
• Created: 2020-11-16T14:50:04.000Z (almost 4 years ago)
• Default Branch: master
• Last Pushed: 2024-04-16T14:29:56.000Z (6 months ago)
• Last Synced: 2024-07-08T11:34:00.331Z (3 months ago)
• Size: 104 KB
• Stars: 11
• Watchers: 4
• Forks: 5
• Open Issues: 1
• Metadata Files:
  • Readme: readme.md
  • License: LICENSE

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README

        
# Mimimal Postgresql client for Jai

This module contains `libpq` bindings as well as some higher-level functions for…

* … connecting to a Postgresql database,

* … executing parameterized queries and

* … optionally parsing the results into a typed array.

It only supports synchronous execution for now.

## Usage

First connect to a Postgresql instance using a connection uri string:

```Jai

connection_str := "postgres://:@:/";

conn, success := connect(connection_str);

defer disconnect(conn);

```

Then use `conn` to execute statements…

```Jai

// Restrict schema access

success = execute(conn, "SELECT pg_catalog.set_config('search_path', 'public', false)");

```

… or execute a query and automatically parse the result into an array of any given type:

```Jai 

query :: #string END

	SELECT * FROM tourist_attractions

	WHERE city = $1 AND price < $2 AND min_age < $3

	ORDER BY name

END

Attraction :: struct {

	name: string;

	city: string;

	price: string; // Numerics are parsed into strings

	min_age: int;

	is_open: bool;

}

// Query parameters can be passed as variadic args after `query`:

city := "Vienna";

price := 50;

min_age := 18;

attractions, success = execute(conn, Attraction, query, city, price, min_age);

```

By default, `execute` fails if the result contains a column that has no corresponding member in the struct type you passed.

You can pass `ignore_unknown = true` to `execute(…)` to ignore unknown columns instead.

If your struct type contains members that aren’t present in the result (or are null), they will be left at their default values.

## Memory model

You’re responsible for freeing everything (including strings) in the result array.

Using a Pool allocator around your `execute` calls might be a good idea.

## Supported query parameter types

* All integer types

* `float` and `float64`

* `string`

## Supported return value column types

* `INT2`, `INT4`, `INT8`

* `FLOAT4`, `FLOAT8`

* `NUMERIC` (currently only parsed into `string` fields)

* `BOOL`

* `CHAR`, `BPCHAR`, `VARCHAR`, `NAME`, `TEXT`

* `DATE`, `TIMESTAMP`, `TIMESTAMPTZ`

* `BYTEA`

* `OID`

* Custom enum types (`CREATE TYPE … AS ENUM`), which can be parsed into `string` or `enum` member fields.