@nano-sql/adapter-scylla/README.md

Easily Use Scylla DB with nanoSQL 2!

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<h1 align="center">nanoSQL 2 Scylla DB Adapter</h1>
<p align="center">
  <strong>Allows you to run Scylla DB / Cassandra with <a href="https://www.npmjs.com/package/@nano-sql/core">nanoSQL 2</a></strong>
</p>

[Documentation](https://nanosql.io/adapters/scylladb.html) | [Bugs](https://github.com/ClickSimply/Nano-SQL/issues) | [Chat](https://gitter.im/nano-sql/community)

# Installation

```sh
npm i @nano-sql/adapter-scylla --save
```

# Usage

```ts
import { Scylla } from "@nano-sql/adapter-scylla";
import { nSQL } from "@nano-sql/core";

nSQL().connect({
    id: "my_db", // used as Scylla Keyspace
    mode: new Scylla({
      contactPoints: ['127.0.0.1:9042']
    }),
    tables: [...]
}).then(...)
```

# API

The `Scylla` class accepts up to three arguments in it's constructor.

### Scylla Connect Options (Required)
The first object is the client connect options, passed into the underlying cassandra driver.  It's fully documented [here](https://docs.datastax.com/en/developer/nodejs-driver/3.6/api/type.ClientOptions/).

### Redis Database Connect Options (Optional)
Redis is needed to store the table indexes, if you pass nothing here the adapter will attempt to connect to a Redis database running on the default port on localhost.  You can optionally pass in a configuration object to adjust things like the port and ip address the client will attempt to connect to.

All of the configuration options are documented [here](https://www.npmjs.com/package/redis#rediscreateclient).

> **Why do I need Redis?  I thought this was a ScyllaDB adapter!** The realities of Scylla's design is that simple data models with range queries like nanoSQL allow aren't possible without sacrificing the reason you're using Scylla.  The Redis indexes allow us to abstract the rabbit hole that is [Scylla Data Modeling](https://www.datastax.com/dev/blog/basic-rules-of-cassandra-data-modeling) from you with minimal performance penalty.  The indexes will work up to 4 billion records per table/secondary index and Redis can easily be configured to be highly available as well.

### Scylla Query Filters (Optional)
Lets you adjust queries before they're sent to the database.  Each property is a function that gets the query string as it's argument and should return a query string to be sent to the database.

Here are the possible queries you can modify, all properties are optional.

| Property         | Query                                 |
|------------------|---------------------------------------|
| createKeySpace   | Create keyspace query.                |
| createTable      | Create table query.                   |
| useKeySpace      | Use keyspace query.                   |
| dropTable        | Drop table query.                     |
| selectRow        | Select one row query.                 |
| upsertRow        | Updating row query.                   |
| deleteRow        | Remove row query.                     |
| createIndex      | Create index query.                   |
| dropIndex        | Drop index query.                     |
| addIndexValue    | Adding a row value to an index query. |
| deleteIndexValue | Removing a row value from an index.   |
| readIndexValue   | Read a row id from an index.          |

# Limitations
Auto increment integer primary keys will *technically* work for small tables, but don't do it.  Use `UUID`s as your primary keys, this will also help guarantee good distribution of data across your cluster.

Avoid queries [that will lead to a full table scan](https://nanosql.io/performance.html) or you'll have a bad time.

# MIT License

Copyright (c) 2019 Scott Lott

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.

# Changelog 

## [2.0.5]
- Dependency and documentation updates.

## [2.0.4]
- Added gitter link

## [2.0.2] & [2.0.3]
- Performance improvements

## [2.0.1]
- Readme fixes

## [2.0.0]
- Initial release