Type mapping

How each database's column types become GraphQL types. A column that is NOT NULL is non-null (Int!); in inputs, it's required unless the database fills it in.

GraphQL	PostgreSQL	MySQL / MariaDB	SQL Server	MongoDB
Int	smallint, integer	tinyint, smallint, mediumint, int	tinyint, smallint, int	integers
Float	real, double precision	float, double, real	real, float	numbers with decimals
Boolean	boolean	boolean, tinyint(1)	bit	booleans
DateTime	date, timestamp, timestamptz	date, datetime, timestamp	date, datetime, datetime2, smalldatetime, datetimeoffset	dates
JSON	json, jsonb	json (MySQL)	—	objects, arrays, mixed types
ID	—	—	—	ObjectIds
String	everything else	everything else	everything else	strings, Decimal128, Long

Why bigint is a String

bigint, numeric and decimal values can exceed what a JavaScript number holds exactly, so drivers return them as strings and the API keeps them that way. A bigserial key is therefore id: String!, and a filter on it takes strings: { id: { eq: "42" } }.

Arrays

PostgreSQL arrays become lists of their element type, such as [String]. They can be filtered with isNull only, and can't be ordered by.

DateTime

Values are serialized as ISO 8601 strings in UTC (2026-10-16T13:45:00.000Z), and inputs accept any ISO 8601 string.

JSON

Any JSON value, stored and returned as is. JSON fields can be filtered with isNull only, and can't be ordered by.