PhoenixmlDb.Core 1.6.0

• net10.0

  • No dependencies.

• net8.0

  • No dependencies.

Range queries over document metadata, and a typed way to declare the index that serves them.
Additive — nothing from 1.5.0 changes shape.

### `QueryMetadataRangeAsync`

Metadata could be queried for equality but not for order, which left the obvious questions —
everything received since a cutoff, everything with a retry count above a threshold — unable to
use an index even when one existed.

```csharp
// everything received on or after the cutoff
await foreach (var d in container.QueryMetadataRangeAsync(Received, lowerBound: cutoff, upperBound: null))
   Console.WriteLine(d.Name);
```

Either bound may be null for an open-ended range; both null matches every document carrying the
property at all. Ordering follows the property's XDM type rather than its .NET string form, so
dates order chronologically and numbers numerically.

As with equality, a declared index changes how the range is found and never what it finds. An
unindexed container answers the same query by scanning, comparing the same order-preserving
encoding the index walks.

**Two overloads, for a reason worth stating.** The typed overload constrains `T : struct`:

```csharp
IAsyncEnumerable<DocumentInfo> QueryMetadataRangeAsync<T>(
   MetadataProperty<T> descriptor, T? lowerBound, T? upperBound, ...) where T : struct;
```

On an unconstrained `T`, `T?` is a nullability annotation rather than `Nullable<T>`, so a
value-typed property could not express an open-ended range at all — `null` would not compile.
Using `default(T)` for "no bound" was the alternative, and it is a lie the caller cannot detect:
an unbounded range would be indistinguishable from one bounded at `DateTimeOffset.MinValue` or
`0`. The second overload takes an `XdmQName` with `XdmValue?` bounds and covers everything the
first cannot, including `MetadataProperty<string>`.

### `AddMetadataIndex<T>`

```csharp
opts.Indexes.AddMetadataIndex(Received, XdmValueType.DateTime);
```

Takes the qualified name from the property rather than restating it, so an index cannot drift
from the values it is meant to cover. The `XdmQName` overload remains for names with no
declared property.