rn-async-database/README.md

A simple database base on react-native AsyncStorage.

## rn-async-database

A simple local database using AsyncStorage for React Native.
Based on [react-native-store](https://github.com/thewei/react-native-store)


### Installation
```bash
$ npm install rn-async-database --save
```
or
```bash
$ yarn add rn-async-database
```

### Data anatomy
```
db_store
   |---model_name
         |---totalrows (variable)
         |---autoinc (variable)
         |---rows (array)
                |--- _id (number)
                |--- ....

```

### API
- **Model( modelName )** : returns a `Model` object
- **Model.add( data, filter )** : returns a `promise` object
- **Model.update( data, filter )** : returns a `promise` object
- **Model.updateById( data, id )** : returns a `promise` object
- **Model.remove( filter )** : returns a `promise` object
- **Model.removeById( id )** : returns a `promise` object
- **Model.find( filter )** : returns a `promise` object
- **Model.findById( id )** : returns a `promise` object
- **Model.get( filter )** : returns a `promise` object
- **Model.destroy()** : returns a `promise` object

### Simple example

```js
import Store from 'rn-async-database';

const database = new Store({ dbName: 'my_database' })
// --> dbName is REQUIRED

const DB = {
    'foo': database.model('foo'),
    'bar': database.model('bar')
}

// somewhere inside react components

componentDidMount() {
    // Return all items
    DB.foo.find().then(resp => this.setState({items: resp}));
}

handleFilter(itemName) {
    DB.foo.find({
        where: {
            and: [{ foo: { neq: itemName } }, { age: { gte: 5 } }]
        },
        order: {
            age: 'ASC',
        }
    }).then(resp => this.setState({items: resp}));
}

handleOnPress() {
    DB.bar.add({
        foo: 'foo',
        bar: 'bar',
        age: 12
    });
}

```

### Advanced Filtering

Filtering adds more advanced logic to queries. This implementation is heavily
based off of [LoopBack's implementation](https://docs.strongloop.com/display/public/LB/Querying+data#Queryingdata-Filters).
However, there are some important things that are different/leftout:

- The [include filter](https://docs.strongloop.com/display/public/LB/Include+filter) is not implemented as it is not relevant.
- The [near and like/nlike](https://docs.strongloop.com/display/public/LB/Where+filter#Wherefilter-likeandnlike) operators are not implemented.
- The [skip filter](https://docs.strongloop.com/display/public/LB/Skip+filter) in LoopBack is the offset filter in this implementation to
  stay consistent with previous versions.

**Note**: Query operations on object nested within an entry are not perfect.
For example, trying to update an entry that looks something like this:

```javascript
{
  location: { name: 'place', distance: 'far' }
}
```

With this as the value of a where filter:

```javascript
{
  location: { name: 'place' }
}
```

Will overwrite the value of `location`, effectively removing the `distance`
property.
This occurs similarly with the order and fields filter, as you can only apply
the filters to values that are not nested within an object.