xs:minLength — Facet to define a minimum length.
<xs:minLength
fixed = xs:boolean : “false”
id = xs:ID
value = xs:nonNegativeInteger
{any attributes with non-schema namespace}
>
Content: (xs:annotation?)
</xs:minLength>
May be included in: xs:restriction (simple type), xs:restriction (simple content)
May be used as facet for: xs:anyURI, xs:base64Binary, xs:ENTITIES, xs:ENTITY, xs:hexBinary, xs:ID, xs:IDREF, xs:IDREFS, xs:language, xs:Name, xs:NCName, xs:NMTOKEN, xs:NMTOKENS, xs:normalizedString, xs:NOTATION, xs:QName, xs:string, xs:token
xs:minLength is a facet that allows definition of
the minimum length expressed in a unit that depends on the datatype.
For most of the datatypes, the unit is the character as defined in
the XML 1.0 Recommendation (i.e., Unicode characters defined by
ISO/IEC 10646 that may be represented on more than 8 bits). The
exceptions are the binary datatypes (xs:hexBinary
and xs:base64Binary), for which lengths are
expressed in number of bytes (8 bits) of binary data, and all the
list datatypes, for which lengths are expressed in number of list
items.
xs:minLength constrains the value space. In
practice, this means that it is checked after whitespace replacement
and collapsing, as defined by the xs:whiteSpace
facet.
This is a logical length, which often has no direct relation on the size of storage needed for the value.
It is forbidden to define both xs:minLength and
xs:length in the same restriction step. Although
not explicitly specified in the Recommendation, it
doesn’t make sense to define several
xs:minLength facets in a single restriction step
either.
Within a restriction step, xs:minLength is also
dependent on xs:maxLength, since using
inconsistent values leads to datatypes with empty value spaces.
xs:minLength must restrict the value space of its
base type, and its value must be greater than the value of
xs:minLength of its base type if defined.
Although not specified in the Recommendation,
xs:minLength interacts with
xs:length and shouldn’t be used
if xs:length is defined for its base type.
Fixing the xs:minLength facet
doesn’t fix the xs:length facet.
To fix both facets, define two restriction steps since it is
forbidden to apply these two facets in the same restriction step.