:sig
u64 DValue::to_u64(u64 default_value = 0) const

:params
u64 : fallback returned when conversion is not possible
return value : converted value or the fallback

:see
0_DValue
2_DValue_get_by_path

:content
Converts strings, f64, bool, pointer, and single-value maps to an unsigned integer. Invalid or empty strings return the default. Negative values clamp to zero and oversized values clamp to `u64` max.

```cpp
u64 id = row["id"].to_u64();
```