XML - Elements in Document Type Definitions (DTD) Page - 2

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DECLARING ELEMENTS WITH MIXED CONTENT

At times it is required to declare elements with mixed content i.e. both data and other elements. In such situations the pipe symbol (|) is used.

SYNTAX < !ELEMENT parent (#CDATA or #PCDATA,child1,child2, . . . , childN) >

Example:

< bank >
This account is Active
< account >123456< /account >
This account is Closed
< account >423578< /account >
< /bank >

DECLARING ELEMENTS WITH ANY CONTENT

In Real world scenarios, the developer is many a times not sure about the exact document structure while creating the DTD. At such times, ANY keyword comes handy. An element declared as ANY can

• Contain child elements
• Contain character data
• Contain mixed content

SYNTAX: < !ELEMENT element_name ANY >

DECLARING ELEMENTS WITH NO CONTENT

Sometimes it is required that an elements has only attributes but no data. In such scenarios the EMPTY keyword is used.

SYNTAX : < !ELEMENT element_name EMPTY >

ELEMENT ORDER INDICATORS AND QUALIFIERS

The various order and qualification governing symbols are listed in the table append below

ORDER

QUALIFIER

EXAMPLES:

The pipe symbol (|) specifies choice. So occurrence of either of the chiold element is considered valid by the parser.

Following declaration specifies that name must contain either first_name or last_name

< !ELEMENT name (fist_name | last_name) >