Analyzer
Schema analyzer for Drizzle ORM projects. Produces a normalized Analysis used by generators.
See the package README for API and output shape.
maxBytes, the cap that is not a character count
A width on a column can mean two different things, and the analyzer carries them as two fields rather than one, because applying the wrong one accepts rows the database refuses.
maxLength is a character limit. varchar(10) is ten characters in both Postgres and MySQL, and that is what the validation generators enforce.
maxBytes is a byte budget, and only MySQL sets it. MySQL's TEXT and BLOB families carry their limit in the type itself rather than in a declared length, and that limit is counted in bytes. On utf8mb4 a tinytext holds 255 ascii characters or 63 emoji, because the 64th emoji is the 256th byte. maxLength cannot express that, and applying the number as a character count is what let a tinytext holding 64 emoji validate clean and then be refused by the server.
Eight column types set it, measured on drizzle-orm 1.0.0-rc.4:
| Column | maxBytes |
|---|---|
tinytext(), tinyblob() | 255 |
text(), blob() | 65535 |
mediumtext(), mediumblob() | 16777215 |
longtext(), longblob() | 4294967295 |
varchar({ length: n }) sets maxLength and no maxBytes, because MySQL really does count that one in characters. A Postgres text column sets neither, because it has no limit.
The two majors differ in what else the column reports. On drizzle-orm 0.45.2 a text() column states no length at all, so maxBytes is the only cap there; on 1.0.0-rc.4 the same column also reports a maxLength equal to it. The blob half of the table is not reachable on 0.45.2 at all: drizzle-orm/mysql-core there exports no blob, tinyblob, mediumblob or longblob.
The Zod, Valibot, ArkType, TypeBox and Effect Schema generators encode maxBytes as a predicate over new TextEncoder().encode(value).length. JSON Schema has no byte-counting keyword, so the JSON Schema generator emits the number as a maxLength, which refuses nothing the column accepts, and states the byte budget in the schema's description.