Prisma String Types to SQL VARCHAR and TEXT

String Type Mapping

Prisma's String type is a versatile text type that maps to different SQL column types depending on the dialect and any @db. annotations you provide.

Default Mapping

Without any @db. annotation, String maps to:

• PostgreSQL: VARCHAR(255)
• MySQL: VARCHAR(255)
• SQLite: VARCHAR(255)

Using @db Annotations

You can control the exact SQL type using Prisma's native database type annotations:

model Article {
  id      Int    @id @default(autoincrement())
  title   String @db.VarChar(200)
  slug    String @db.VarChar(100) @unique
  content String @db.Text
  code    String @db.Char(6)

  @@map("articles")
}

Generated SQL (PostgreSQL)

CREATE TABLE articles (
  id SERIAL PRIMARY KEY,
  title VARCHAR(200) NOT NULL,
  slug VARCHAR(100) NOT NULL UNIQUE,
  content TEXT NOT NULL,
  code CHAR(6) NOT NULL
);

Annotation Reference

Prisma annotation	PostgreSQL	MySQL	SQLite
String (default)	VARCHAR(255)	VARCHAR(255)	VARCHAR(255)
@db.Text	TEXT	TEXT	TEXT
@db.VarChar(n)	VARCHAR(n)	VARCHAR(n)	VARCHAR(n)
@db.Char(n)	CHAR(n)	CHAR(n)	CHAR(n)
@db.Uuid	UUID	VARCHAR(36)	VARCHAR(36)

UUID Fields

For UUID primary keys, Prisma's @db.Uuid annotation is particularly useful with PostgreSQL, which has a native UUID type:

model Session {
  id String @id @default(uuid()) @db.Uuid
}

This generates id UUID PRIMARY KEY DEFAULT gen_random_uuid() for PostgreSQL.