Hasql is a highly efficient PostgreSQL driver and a mapping API. It targets both the users, who need a low level of abstraction, and the users, who face the typical tasks of DB-powered applications, providing them with higher-level APIs.
* ["hasql"](https://github.com/nikita-volkov/hasql) - the root of the ecosystem, which provides the essential abstraction over the PostgreSQL client functionality and mapping of values. Everything else revolves around that library.
* ["hasql-dynamic-statements"](https://github.com/nikita-volkov/hasql-dynamic-statements) - a toolkit for generating statements based on the parameters.
* ["hasql-cursor-transaction"](https://github.com/nikita-volkov/hasql-cursor-transaction) - a lower-level abstraction over cursors, which however allows to fetch from multiple cursors simultaneously. Generally though "hasql-cursor-query" is the recommended alternative.
* **Flexibility and composability.** The user picks and chooses the features, thus precisely matching the level of abstraction that he needs for his task.
* **Much more stable and more descriptive semantic versioning.** E.g., a change in the API of the "hasql-transaction" library won't affect any of the other libraries and it gives the user a more precise information about which part of his application he needs to update to conform.
* **Interchangeability and competition of the ecosystem components.** E.g., [not everyone will agree](https://github.com/nikita-volkov/hasql/issues/41) with the restrictive design decisions made in the "hasql-transaction" library. However those decisions are not imposed on the user, and instead of having endless debates about how to abstract over transactions, another extension library can simply be released, which will provide a different interpretation of what the abstraction over transactions should be.
* **Horizontal scalability of the ecosystem.** Instead of posting feature- or pull-requests, the users are encouraged to release their own small extension-libraries, with themselves becoming the copyright owners and taking on the maintenance responsibilities. Compare this model to the classical one, where some core-team is responsible for everything. One is scalable, the other is not.
For the general use-case it is advised to prefer declaring statements using the "hasql-th" library, which validates the statements at compile-time and generates codecs automatically. So the above two statements could be implemented the following way:
```haskell
import qualified Hasql.TH as TH -- from "hasql-th"