What data types exist in XSD?

In XSD (XML Schema Definition), there are built-in and derived data types.

Built-in data types are divided into primitive and derived from primitive:

Primitive types:

• xsd:string: a sequence of characters.
• xsd:boolean: a logical value (true or false, 1 or 0).
• xsd:decimal: a floating-point number based on decimal representation.
• xsd:float: a 32-bit floating-point number based on IEEE 754.
• xsd:double: a 64-bit floating-point number based on IEEE 754.
• xsd:duration: a time interval.
• xsd:dateTime: date and time.
• xsd:time: time of day.
• xsd:date: date.
• xsd:gYearMonth: month and year.
• xsd:gYear: year.
• xsd:gMonthDay: month and day.
• xsd:gDay: day of the month.
• xsd:gMonth: month.
• xsd:hexBinary: binary data encoded in hexadecimal format.
• xsd:base64Binary: binary data encoded in Base64.
• xsd:anyURI: universal resource identifier (URI).
• xsd:QName: qualified name (namespace prefix + local name).
• xsd:NOTATION: reference to an XML notation declaration.

Derived from primitive types:

• xsd:normalizedString: a string where line breaks, carriage returns, and tabs are replaced with spaces.
• xsd:token: a string without leading/trailing spaces and with sequences of spaces replaced by a single space.
• xsd:language: language code according to RFC 3066.
• xsd:NMTOKEN: an XML name token.
• xsd:NMTOKENS: a list of XML name tokens separated by spaces.
• xsd:Name: an XML name.
• xsd:NCName: an XML name without a colon.
• xsd:ID: a unique identifier in an XML document.
• xsd:IDREF: a reference to an xsd:ID.
• xsd:IDREFS: a list of references to IDs.
• xsd:ENTITY: an unparsed XML entity.
• xsd:ENTITIES: a list of unparsed XML entities.
• xsd:integer: an integer of arbitrary precision.
• xsd:long: a 64-bit signed integer.
• xsd:int: a 32-bit signed integer.
• xsd:short: a 16-bit signed integer.
• xsd:byte: an 8-bit signed integer.
• xsd:nonPositiveInteger: an integer ≤ 0.
• xsd:negativeInteger: an integer < 0.
• xsd:nonNegativeInteger: an integer ≥ 0.
• xsd:positiveInteger: an integer > 0.
• xsd:unsignedLong: a 64-bit unsigned integer.
• xsd:unsignedInt: a 32-bit unsigned integer.
• xsd:unsignedShort: a 16-bit unsigned integer.
• xsd:unsignedByte: an 8-bit unsigned integer.

Derived data types:

Can be defined by the user through restriction, extension, list, or union of existing types.

Example of defining a custom type:

<xsd:simpleType name="age">
  <xsd:restriction base="xsd:integer">
    <xsd:minInclusive value="0"/>
    <xsd:maxInclusive value="150"/>
  </xsd:restriction>
</xsd:simpleType>