T046, “CLOB data type”

1. Without the synonyms character large object and char large object
2. Without length limit: clob(1)
3. Without the mandatory multipliers k, m and g
4. Without the synonym char large object

The character large object type is, like all large object types, limited to fewer operations than their other character string relatives. They are, for example, disallowed in primary keys and foreign key constraints as only support the equality (=) comparisons. “Applications would typically not transfer entire LOB values to and from the database (after initial storage, that is), but would manipulate LOB values through a special client-side type called a LOB locator.”

The optional length limit can use kilo, mega, giga, tera and peta factors (powers of two).

Related

Supplementary Features

• T043, “Multiplier T”

• T044, “Multiplier P”

Mandatory Features

• E021-01, “CHARACTER data type (including all its spellings)”

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

Optional Features

• F421, “National character”

• T062, “Character length units”

• T081, “Optional string types maximum length”

Implementation-defined Elements

• ID068, “The implicit large object length when large object length is omitted.”

• IL042, “The maximum lengths for character string types and binary string types.”

Normative References

The types character large object, char large object, clob, national character large object, nchar large object and nclob are defined in ISO/IEC 9075-2:2023 as part of the optional feature T046, “CLOB data type”. They first appeared in 1999.