DTD attribute token types allow only certain value in a specific structure. following are some token type.
CDATA
CDATA specifies the character string type data.
Syntax
<ATTLIST element_name attr_name CDATA attr_declaration>
Example
<?xml version="1.0" standalone="yes"?>
<!DOCTYPE empinfo [
<!ELEMENT empinfo (employee)>
<!ELEMENT employee (designation)>
<!ELEMENT designation (#PCDATA)>
<!ATTLIST designation discipline CDATA "web_developer">
]>
<empinfo>
<employee id="1">
<designation>Senior Engineer</designation>
</employee>
<employee id="2">
<designation discipline="DBA">Senior Engineer</designation>
</employee>
</empinfo>
Example Result
ID
ID specifies the unique identifier. No element can have same ID in XML document.
Syntax
<ATTLIST element_name attr_name ID attr_declaration>
Example
<?xml version="1.0" standalone="yes"?>
<!DOCTYPE empinfo [
<!ELEMENT empinfo (employee)>
<!ELEMENT employee (designation)>
<!ATTLIST employee id CDATA #REQUIRED>
<!ELEMENT designation (#PCDATA)>
<!ATTLIST designation discipline CDATA "web_developer">
]>
<empinfo>
<employee id="1">
<designation>Senior Engineer</designation>
</employee>
<employee id="2">
<designation discipline="DBA">Senior Engineer</designation>
</employee>
</empinfo>
Example Result
IDREF
IDREF specifies to a another elements id attribute value.
Syntax
<ATTLIST element_name attr_name IDREF attr_declaration>
Example
<?xml version="1.0" standalone="yes"?>
<!DOCTYPE empinfo [
<!ELEMENT empinfo (employee)>
<!ELEMENT employee (designation)>
<!ATTLIST employee id ID #REQUIRED>
<!ATTLIST employee user_id IDREF #REQUIRED>
<!ELEMENT designation (#PCDATA)>
]>
<empinfo>
<employee id="1" user_id="2">
<designation>Senior Engineer</designation>
</employee>
<employee id="2" user_id="3">
<designation>Senior Engineer</designation>
</employee>
<employee id="3" user_id="1">
<designation>Senior Engineer</designation>
</employee>
</empinfo>
Example Result
IDREFS
IDREFS specifies one or more ID reference value separated by blank spaces.
Syntax
<ATTLIST element_name attr_name IDREFS attr_declaration>
Example
<?xml version="1.0" standalone="yes"?>
<!DOCTYPE empinfo [
<!ELEMENT empinfo (employee)>
<!ELEMENT employee (designation)>
<!ATTLIST employee id ID #REQUIRED>
<!ATTLIST employee user_id IDREFS #IMPLIED>
<!ELEMENT designation (#PCDATA)>
]>
<empinfo>
<employee id="1" user_id="2 3">
<designation>Senior Engineer</designation>
</employee>
<employee id="2">
<designation>Senior Engineer</designation>
</employee>
<employee id="3">
<designation>Senior Engineer</designation>
</employee>
</empinfo>
Example Result
ENTITY
ENTITY refer to a name of the entity. Allow only specified entity.
Syntax
<ATTLIST element_name attr_name IDREFS attr_declaration>
<ENTITY entity_name entity_definition>
...
Example
<?xml version="1.0" standalone="yes"?>
<!DOCTYPE empinfo [
<!ELEMENT empinfo (employee)>
<!ELEMENT employee (designation)>
<!ELEMENT designation (#PCDATA)>
<!ATTLIST designation discipline ENTITY #IMPLIED>
<!ENTITY web "web_developer">
<!ENTITY dba "DBA">
]>
<empinfo>
<employee>
<designation discipline="&web;">Senior Engineer</designation>
</employee>
<employee>
<designation discipline="&dba;">Administrator</designation>
</employee>
</empinfo>
Example Result
ENTITIES
ENTITIES refer to a list of entity name separated by blank spaces.
Syntax
<ATTLIST element_name attr_name ENTITIES attr_declaration>
<ENTITY entity_name entity_definition>
...
Example
<?xml version="1.0" standalone="yes"?>
<!DOCTYPE empinfo [
<!ELEMENT empinfo (employee)>
<!ELEMENT employee (designation)>
<!ELEMENT designation (#PCDATA)>
<!ATTLIST designation discipline ENTITIES #IMPLIED>
<!ENTITY web "web_developer">
<!ENTITY dba "DBA">
<!ENTITY soft "software_developer">
]>
<empinfo>
<employee>
<designation discipline="&web; &soft;">Senior Engineer</designation>
</employee>
<employee>
<designation discipline="&dba;">Administrator</designation>
</employee>
</empinfo>
Example Result
NMTOKEN
NMTOKEN specifies the any string character exclude whitespace. Before and after whitespace automatic trimmed.
Syntax
<ATTLIST element_name attr_name NMTOKEN attr_declaration>
Example
<?xml version="1.0" standalone="yes"?>
<!DOCTYPE empinfo [
<!ELEMENT empinfo (employee)>
<!ELEMENT employee (designation)>
<!ELEMENT designation (#PCDATA)>
<!ATTLIST designation discipline NMTOKEN "web_developer">
]>
<empinfo>
<employee>
<designation>Developer</designation>
</employee>
<employee>
<designation discipline="DBA">Senior Engineer</designation>
</employee>
<employee>
<designation discipline="software_developer">Administrator</designation>
</employee>
</empinfo>
Example Result
NMTOKENS
NMTOKENS specifies the multiple NMTOKEN separated by whitespace.
Syntax
<ATTLIST element_name attr_name NMTOKENS attr_declaration>
Example
<?xml version="1.0" standalone="yes"?>
<!DOCTYPE empinfo [
<!ELEMENT empinfo (employee)>
<!ELEMENT employee (designation)>
<!ELEMENT designation (#PCDATA)>
<!ATTLIST designation discipline NMTOKENS "web_developer Trainee">
]>
<empinfo>
<employee>
<designation>Developer</designation>
</employee>
<employee>
<designation discipline="DBA software_developer">Senior Engineer</designation>
</employee>
</empinfo>
Example Result
