When requiring the module you will end up with the `wgdb` class which is how you
interact with WhiteDB
#### CONSTANTS
* `wgdb.EQUAL` - used to represent `=` condition for queries
* `wgdb.NOT_EQUAL` - used to represent `!=` condition for queries
* `wgdb.LESSTHAN` - used to represent `<` condition for queries
* `wgdb.GREATER` - used to represent `>` condition for queries
* `wgdb.LTEQUAL` - used to represent `<=` condition for queries
* `wgdb.GTEQUAL` - used to represent `>=` condition for queries
#### `new wgdb(db_name, [size])`
Creates a new instance of `wgdb`.
* `db_name` - integer name of shared memory space (required)
* `size` - the size in bytes for the databae if it does not already exist (default: 10000000 - 10MB)
```javascript
var wgdb = require("wgdb");
var db = new wgdb(1000, 2000000);
```
#### `wgdb.attach([callback])`
Either attaches to or creates the shared space for the `wgdb` instance.
Calling `attach` is very important, this makes it so you can use the other methods.
* `callback` - `function(error)` to call when done attaching, `error` will be `undefined` if no error occurred.
```javascript
var wgdb = require("wgdb");
var db = new wgdb(1000, 2000000);
db.attach(function(error){
if(error){
console.log(error);
}
// do some cool stuff
});
```
#### `wgdb.detach([callback])`
Detaches an attached `wgdb` instance.
* `callback` - `function(error)` to call when done detaching, `error` will be `undefined` if no error occurred.
```javascript
var wgdb = require("wgdb");
var db = new wgdb(1000, 2000000);
db.attach(function(error){
if(!error){
// do some cool stuff
db.detach(console.log);
}
});
```
#### `wgdb.delete([callback])`
Delete the shared memory space for the `wgdb` instance.
* `callback` - `function(error)` to call when done deleting, `error` will be `undefined` if no error occurred.
```javascript
var wgdb = require("wgdb");
var db = new wgdb(1000, 2000000);
db.attach(function(error){
if(!error){
db.delete(console.log);
}
});
```
#### `wgdb.dump(filename, [callback])`
Dump the `wgdb` database to `filename`.
* `filename` - string filename of where to dump the database (required)
* `callback` - `function(error)` to call when done dumping, `error` will be `undefined` if no error occurred.
```javascript
var wgdb = require("wgdb");
var db = new wgdb(1000, 2000000);
db.attach(function(error){
if(!error){
db.dump("backup.db", console.log);
}
});
```
#### `wgdb.import(filename, [callback])`
Import `filename` into the `wgdb` database.
* `filename` - string filename of where to load the database from (required)
* `callback` - `function(error)` to call when done importing, `error` will be `undefined` if no error occurred.
```javascript
var wgdb = require("wgdb");
var db = new wgdb(1000, 2000000);
db.attach(function(error){
if(!error){
db.import("backup.db", console.log);
}
});
```
#### `wgdb.createRecord(num_fields, [callback])`
Add a new record to the `wgdb` instance.
* `num_fields` - int number of fields for the record to have (required)
* `callback` - `function(error, record)` to call when done creating, `error` will be `undefined` if no error occurred, `record` will be `undefined` if an error occurred or else will be a `record` instance.
```javascript
var wgdb = require("wgdb");
var db = new wgdb(1000, 2000000);
db.attach(function(error){
if(!error){
db.createRecord(2, function(error, record){
if(error || !record){
console.log(error);
return;
}
// do some cool record stuff here
});
}
});
```
#### `wgdb.firstRecord([callback])`
Get the first record from the `wgdb` instance.
* `callback` - `function(error, record)` to call when done creating, `error` will be `undefined` if no error occurred, `record` will be `undefined` if an error occurred or else will be a `record` instance.
```javascript
var wgdb = require("wgdb");
var db = new wgdb(1000, 2000000);
db.attach(function(error){
if(!error){
db.firstRecord(function(error, record){
if(error || !record){
console.log(error);
return;
}
// do some cool record stuff here
});
}
});
```
#### `wgdb.findRecord(field, condition, value [last_record], [callback])`
Find the first record in the `wgdb` database which meets the `condition` and `value` requirements.
If `last_record` is given, then find the first record after `last_record` which meets the conditions.
* `field` - int of the field to search by (required)
* `condition` - one of the `wgdb` condition constants, e.g. `wgdb.EQUAL` (required)
* `value` - the value to match `condition` on (required)
* `last_record` - a `record` instance, find the next record after `last_record` which matches `condition` and `value` (optional)
* `callback` - `function(error, record)` to call when done searching, `error` will be `undefined` if no error occurred, `record` will be `undefined` if an error occurred or else will be a `record` instance.
Query the `wgdb` instance for all records which meet the provided `query`.
`query` is similar to a list of parameters to `wgdb.findRecord`.
```javascript
[
[<field_num>, <condition>, <value>],
...
]
```
* `query` - array representing the query to make (required)
* `callback` - `function(error, cursor)` to call when done searching, `error` will be `undefined` if no error occurred, `cursor` will be `undefined` if an error occurred or else will be a `cursor` instance.
