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https://github.com/kamirus/purescript-selda
A type-safe, high-level SQL library for PureScript
https://github.com/kamirus/purescript-selda
edsl nested-queries postgresql purescript purescript-selda query query-language row-polymorphism sql sql-library sqlite3
Last synced: 1 day ago
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A type-safe, high-level SQL library for PureScript
- Host: GitHub
- URL: https://github.com/kamirus/purescript-selda
- Owner: Kamirus
- License: mit
- Created: 2018-10-28T09:48:04.000Z (about 6 years ago)
- Default Branch: master
- Last Pushed: 2023-03-02T17:29:50.000Z (over 1 year ago)
- Last Synced: 2024-11-02T15:09:39.376Z (3 days ago)
- Topics: edsl, nested-queries, postgresql, purescript, purescript-selda, query, query-language, row-polymorphism, sql, sql-library, sqlite3
- Language: PureScript
- Homepage:
- Size: 473 KB
- Stars: 89
- Watchers: 6
- Forks: 3
- Open Issues: 31
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# purescript-selda
[](https://github.com/Kamirus/purescript-selda/actions)
## About
**purescript-selda** is an **SQL library** (*eDSL*) which allows a user to write **type-safe queries**.
- Generated SQL is guaranteed to be correct by the type system.
- It supports **arbitrarily nested queries** with capabilities of **filtering**, **joins** and **aggregation**.
- We used **standard monadic abstraction** which supports writing queries in a linear, natural style.
- Our main target is **PostgreSQL** though in the upcoming release (already on master) we add **SQLite3** support (with ability to support other db backends).
## Example Query
To declare a type for a SQL table (already created in the db)
we write the following table definition:
```purescript
people ∷ Table (id ∷ Int, name ∷ String, age ∷ Maybe Int)
people = Table { name: "people" }
```
Once we've defined the tables, we can write queries, e.g.
```purescript
selectFrom people \{ id, name, age } → do
{ balance } ← leftJoin bankAccounts \b → id .== b.personId
restrict $ id .> lit 1
pure { id, balance }
```
Generated SQL for the above query:
```sql
SELECT people_0.id AS id, bank_accounts_1.balance AS balance
FROM people people_0
LEFT JOIN bank_accounts bank_accounts_1 ON ((people_0.id = bank_accounts_1.personId))
WHERE ((people_0.id > 1))
```
For a more gentle introduction and more examples please refer to the [Step-by-Step Guide](guide/SimpleE2E.md).
## More Help
**If you have any questions please don't hesitate to ask**.
I'll be happy to help and provide any guidance if necessary.
Open an issue or hit me up directly (either on [slack](https://functionalprogramming.slack.com/), [forum](https://discourse.purescript.org/) or directly via email).
## Install
Install [postgresql-client's dependencies](https://github.com/rightfold/purescript-postgresql-client#install)
> npm install pg decimal.js
## Info
- [**Introductory Guide**](guide/SimpleE2E.md): End-to-End example: how to setup, write queries, use aggregation, deal with type errors and execute queries and inserts.
- [**Advanced Guide**](guide/Custom.md): Custom Types and Expressions (`litPG`, `Any`, `EForeign`, custom PG functions), more flexible table definitions (`Source`, db schemas, set-returning functions) - unsafe escape hatches
- **Test Suite**: For information about features, examples, usage, etc. refer to the test suite: [`Test.Common`](test/Common.purs), [`Test.PG`](test/PG.purs), [`Test.SQLite3`](test/SQLite3.purs). To run the tests, `docker-compose up -d` helps to prepare postgres database.
- **Documentation**: [Pursuit docs](https://pursuit.purescript.org/packages/purescript-selda/)
- [**My thesis**](./selda.pdf)
## Credits
Supported by [Lambda Terms](https://github.com/lambdaterms/)
Inspired by [selda](https://github.com/valderman/selda)