Function json_value_to_string 

pub fn json_value_to_string(val: &Value) -> String

Convert a JSON value to its string representation for use as a SQL parameter.

Kept for back-compat with callers that need a textual fallback (e.g. human-readable logs). New code should bind through JsonParam so integers/booleans/nulls reach Postgres in their typed form instead of collapsing to TEXT, which the driver can’t coerce into INTEGER / BOOLEAN / TIMESTAMPTZ columns and which silently turns JSON null into an empty string for FK columns.