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Update README.md
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louischatriot committed Jan 17, 2016
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Expand Up @@ -271,10 +271,17 @@ db.find({ planet: { $regex: /ar/, $nin: ['Jupiter', 'Earth'] } }, function (err,
```

#### Array fields
When a field in a document is an array, NeDB first tries to see if there is an array-specific comparison function (for now there is only `$size`) being used
and tries it first. If there isn't, the query is treated as a query on every element and there is a match if at least one element matches.
When a field in a document is an array, NeDB first tries to see if the query value is an array to perform an exact match, then whether there is an array-specific comparison function (for now there is only `$size`) being used. If not, the query is treated as a query on every element and there is a match if at least one element matches.

```javascript
// Exact match
db.find({ satellites: ['Phobos', 'Deimos'] }, function (err, docs) {
// docs contains Mars
})
db.find({ satellites: ['Deimos', 'Phobos'] }, function (err, docs) {
// docs is empty
})

// Using an array-specific comparison function
// Note: you can't use nested comparison functions, e.g. { $size: { $lt: 5 } } will throw an error
db.find({ satellites: { $size: 2 } }, function (err, docs) {
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