T081, “Optional string types maximum length”

1. Very low implementation-defined limit: 1
2. Supports varchar(max) as reasonably long length limit

The optional feature T081 allows omitting the length limit for the varchar, nvarchar and varbinary types—including their synonyms character varying, char varying, national character varying, national char varying, nchar varying and binary varying.

CREATE TABLE … (
  s VARCHAR(…)
)

If omitted, an implementation-defined limit applies✓✗. Note that these limits are sometimes as low as “1”.

The large object types allow omitting the length limit even without feature T081—thus the length limit was also optional for them before T081 was introduced in 2023.

There are also non-standard string types that can be declared without length limit.

1. Including tinytext, mediumtext, longtext and ntext
2. Including tinytext, mediumtext and longtext
3. Including ntext

Related

Mandatory Features

• E021-02, “CHARACTER VARYING data type (including all its spellings)”

Optional Features

• F421, “National character”

Implementation-defined Elements

• ID069, “The implicit character maximum length when character maximum length is omitted.”