tciuro/NanoStore — pull request #31 by siuying (2012-05-29 03:50:39+00:00)
Title: Empty search expressions should return all objects, not none

When i create search using expressions array, i found that if the array is empty, the SQL generated will return no result:

```sql
SELECT DISTINCT (NSFKey),NSFPlist,NSFObjectClass FROM NSFKeys WHERE (NSFObjectClass = 'User') AND NSFKey IN ()
```

This pull request fix that and return all results with following SQL:

```sql
SQL: SELECT DISTINCT (NSFKey),NSFPlist,NSFObjectClass FROM NSFKeys WHERE (NSFObjectClass = 'User') AND NSFKey IN (SELECT NSFKEY FROM NSFValues)
```