Rust and Postgres

Introductin

Quick into to Rust and Postgres

Rust and Postgres Types

PostgreSQL Type	Description	Rust Type	Notes
smallint, int2	2-byte signed integer	i16
integer, int4	4-byte signed integer	i32	Most common integer type
bigint, int8	8-byte signed integer	i64
serial, serial4	Auto-incrementing int4	i32	Often used for primary keys
bigserial, serial8	Auto-incrementing int8	i64
real, float4	4-byte float	f32
double precision, float8	8-byte float	f64
numeric, decimal	Arbitrary precision	rust_decimal::Decimal	Requires `postgres-decimal` crate
money	Currency amount	i64 or custom type	Often wrapped for precision
boolean	True/false	bool
character varying(n), varchar(n)	Variable-length string	String
character(n), char(n)	Fixed-length string	String
text	Unbounded string	String
bytea	Binary data	Vec<u8>
date	Calendar date	chrono::NaiveDate
timestamp	Date and time (no timezone)	chrono::NaiveDateTime
timestamptz	Date and time with timezone	chrono::DateTime<Utc> or <FixedOffset>
time	Time of day	chrono::NaiveTime
timetz	Time with timezone	chrono::DateTime<FixedOffset>
interval	Time span	postgres_types::Interval or custom
uuid	Universally unique ID	uuid::Uuid
json, jsonb	JSON data	serde_json::Value
enum	Custom enum	Rust enum with #[derive(ToSql, FromSql)]
composite	Structured type	Rust struct with #[derive(ToSql, FromSql)]

Macro to Do the Mapping

Here is a macro to enable getting of Postgres type to Rust type

#[macro_export]
macro_rules! get_field {
    ($row:expr, $col:expr, $type:ty) => {{
        $row.try_get::<_, $type>($col).map_err(|e| {
            crate::types::DatabaseError::Deserialization {
                column: $col.to_string(),
                source: e,
            }
        })?
    }};
}