# Eddb

<div align="center">
  <img src="https://img.shields.io/badge/Written%20in-elixir-%238238ab?style=for-the-badge" />
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<br />

`eddb` is a distributed database for unstructured data

## Functions

### get

`get` will retrive the data from all neighbors and check which update is the newest.
Only the newest data will be returned.

> [!NOTE]
> This has no affect on the data on the current node.
> If you want the data to be merged, call the `sync` function

```elixir
Database.Database.get_worker("worker1")
|> GenServer.call({:get, "topic", "key"})
```

### get_local

`get_local` will only retrive the newest data from the current node.
Thus, this operation is significantly faster.

```elixir
Database.Database.get_worker("worker1")
|> GenServer.call({:get_local, "topic", "key"})
```

### put

`put` will store the data on the current node.
Data with the same key in the same topic will be overwritten, but the old data will be kept in the history.

```elixir
Database.Database.get_worker("worker1")
|> GenServer.call({:put, "topic", "key", "value"})
```

### put (With optimistic locking)

`put` with optimistic locking is similar to the normal put operation.
However, you can specify the expected current state and **only** if the expection matches with the data on the node, the new data will be stored.

> [!NOTE]
> In some cases you want the data to be expected on all nodes, this can currently only be somewhat archived by calling the `sync` function before

```elixir
Database.Database.get_worker("worker1")
|> GenServer.call({:put, "topic", "key", "currentValue", "newValue"})
```

### sync

`sync` will merge the data from all neighbors.
The data with the newest timestamp is considered the current state.

```elixir
Database.Database.get_worker("worker1")
|> GenServer.call({:sync, "topic"})
```

### delete

`delete` will delete data globally, however, this does only garantee that data is gone if all nodes are fully connected.
Otherwise, a node that still has the data will present it on every `get`-request (not `get_local`).

A better solution would be setting the value to nil or any other placeholder value as the newer timestamp would make it the source-of-truth.

```elixir
Database.Database.get_worker("worker1")
|> GenServer.call({:delete, "topic", "key"})
```