What scalar types does Prisma support?

Prisma's built-in scalars are String, Boolean, Int, BigInt, Float, Decimal, DateTime, Json and Bytes. Each maps to a sensible database column by default, which you can override with a @db native-type attribute.

What is the difference between Float and Decimal?

Float is a double-precision IEEE 754 floating-point number and is subject to rounding error, suitable for measurements. Decimal is an exact fixed-precision number backed by a library, the right choice for money where rounding errors are unacceptable.

How do I change the underlying database type?

Append a @db native-type attribute, for example @db.VarChar(255) on a String or @db.Timestamptz(3) on a DateTime. The native type must be compatible with the Prisma scalar and is specific to your database provider.

How are relations declared?

A relation field references another model by its type, with a @relation attribute naming the foreign-key fields and references. The non-list side typically holds the scalar foreign-key field, while the other side is a list for one-to-many.

Can a field be optional or a list?

Yes. Append ? to make a field nullable (optional) and [] to make it a list. For example String? is a nullable string and Int[] is a scalar list, which Prisma maps to a native array on PostgreSQL.

Prisma Schema Field Types

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Prisma schema field types

Every field in a Prisma model has a type: a built-in scalar, an enum, another model (a relation), or a composite type. Each scalar maps to a default database column that you can override with a @db native-type modifier. This searchable reference lists the scalar types, relation forms and native modifiers with their default PostgreSQL mapping so you can model schemas precisely.

How it works

A field is name Type modifiers attributes. Optionality and lists are encoded with ? and [], and native database types are set with @db:

model User {
  id        Int      @id @default(autoincrement())
  email     String   @unique @db.VarChar(320)
  balance   Decimal  @db.Decimal(12, 2)
  createdAt DateTime @default(now()) @db.Timestamptz(3)
  metadata  Json?
  posts     Post[]
}

The Prisma scalar (String, Decimal, DateTime) chooses the default column, and the @db attribute pins the exact native type. Relations link models by referencing the related model type plus a @relation mapping.

Tips and notes

Use Decimal (never Float) for money to avoid floating-point rounding.
DateTime defaults to timestamp(3); use @db.Timestamptz to store the zone.
Json is great for flexible blobs but cannot be deeply queried portably.
Append ? for nullable and [] for list; BigInt maps to 64-bit integers.