Database schema and ORM for zino.

Supported database drivers

The following optional features are available:

Feature flag	Description	Default?
`orm-mariadb`	Enables the MariaDB database driver.	No
`orm-mysql`	Enables the MySQL database driver.	No
`orm-postgres`	Enables the PostgreSQL database driver.	No
`orm-sqlite`	Enables the SQLite database driver.	No
`orm-tidb`	Enables the TiDB database driver.	No

Mappings of Rust data types

Rust type	MySQL datatype	PostgreSQL datatype	SQLite datatype
`bool`	BOOLEAN	BOOLEAN	BOOLEAN
`i8`	TINYINT	SMALLINT	INTEGER
`u8`	TINYINT UNSIGNED	SMALLINT	INTEGER
`i16`	SMALLINT	SMALLINT	INTEGER
`u16`	SMALLINT UNSIGNED	SMALLINT	INTEGER
`i32`, `Option<i32>`	INT	INT, SERIAL	INTEGER
`u32`, `Option<u32>`	INT UNSIGNED	INT, SERIAL	INTEGER
`i64`, `Option<i64>`, `isize`	BIGINT	BIGINT, BIGSERIAL	INTEGER
`u64`, `Option<u64>`, `usize`	BIGINT UNSIGNED	BIGINT, BIGSERIAL	INTEGER
`f32`	FLOAT	REAL	REAL
`f64`	DOUBLE	DOUBLE PRECISION	REAL
`Decimal`	NUMERIC	NUMERIC	TEXT
`String`, `Option<String>`	TEXT, VARCHAR(255)	TEXT	TEXT
`Date`, `NaiveDate`	DATE	DATE	DATE
`Time`, `NaiveTime`	TIME	TIME	TIME
`DateTime`	TIMESTAMP(6)	TIMESTAMPTZ	DATETIME
`NaiveDateTime`	DATETIME(6)	TIMESTAMP	DATETIME
`Uuid`, `Option<Uuid>`	CHAR(36), UUID	UUID	TEXT
`Vec<u8>`	BLOB	BYTEA	BLOB
`Vec<i32>`, `Vec<u32>`	JSON	INT[]	TEXT
`Vec<i64>`, `Vec<u64>`	JSON	BIGINT[]	TEXT
`Vec<f32>`	JSON	REAL[]	TEXT
`Vec<f64>`	JSON	DOUBLE PRECISION[]	TEXT
`Vec<String>`	JSON	TEXT[]	TEXT
`Vec<UUID>`	JSON	UUID[]	TEXT
`Map`	JSON	JSONB	TEXT