XML Basics Quiz

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Questions and Answers

What is required for characters < and & when used in text within XML?

They must be omitted entirely.

They must be escaped as character entities. (correct)

They can be replaced with any other character.

They must be included as they are.

In well-formed XML, how many parents can a non-root element have?

None.

Any number.

Exactly one. (correct)

Two or more.

Which of the following is a requirement for attribute values in XML?

They are optional.

They can be unquoted.

They must be delimited with quotation marks. (correct)

They must be numeric.

What does it mean for an XML document to be well-formed?

It conforms to the syntax rules of XML. Signup and view all the answers

Which of the following is NOT a valid syntax rule for XML comments?

A comment must not contain the string “--”. Signup and view all the answers

What must be included in the prolog of an XML document?

The version of XML and the character set encoding Signup and view all the answers

Which of the following is true about XML element names?

They must start with a letter or underscore Signup and view all the answers

Which statement describes a requirement for a well-formed XML document?

Every opening tag must have a corresponding end tag Signup and view all the answers

What is a characteristic of XML attributes?

Require a value for every attribute Signup and view all the answers

Where can XML comments be placed within the document?

Anywhere within the document Signup and view all the answers

What starts an XML processing instruction?

<?xml Signup and view all the answers

Which of the following correctly describes a well-formed XML document?

All tags must be closed and properly nested Signup and view all the answers

What must attribute values be enclosed in?

Quotation marks Signup and view all the answers

What is the purpose of entity references in XML?

To replace special characters with predefined values Signup and view all the answers

Which statement accurately describes a CDATA section in XML?

It instructs the parser to ignore certain characters. Signup and view all the answers

What differentiates a well-formed XML document from a valid one?

A well-formed document only checks for syntax correctness. Signup and view all the answers

Which of the following correctly represents a general entity reference for the ampersand character?

& Signup and view all the answers

What happens if an XML parser encounters a missing closing tag?

It reports an error and stops processing. Signup and view all the answers

Which of the following is a valid named character entity in XML for the character 'à'?

à Signup and view all the answers

How do numbered character entities represent characters in XML?

Using their Unicode code point value. Signup and view all the answers

Which syntax error will an XML parser NOT attempt to correct?

Missing closing tags Signup and view all the answers

What is NOT one of the four parts of a Formal Public Identifier (FPI)?

Name of the DTD author Signup and view all the answers

Which of the following types allows an element to contain both character data and child elements?

mixed Signup and view all the answers

What does the cardinality symbol '*' signify in defining elements?

Zero or more instances allowed Signup and view all the answers

In a grouping of elements, which operator is used for sequencing?

, Signup and view all the answers

What does the '?' symbol denote when defining element cardinality?

Zero or one instance allowed Signup and view all the answers

Which attribute modifier indicates that an attribute must be present?

#REQUIRED Signup and view all the answers

What limitation of DTDs prevents them from adequately expressing data types?

Weak data typing Signup and view all the answers

Which of the following is an attribute type defined in DTDs?

ENTITY Signup and view all the answers

What does the #FIXED modifier ensure about an attribute?

It will always have the same value Signup and view all the answers

Which attribute type allows for multiple values in DTDs?

NMTOKENS Signup and view all the answers

What does Document Type Definition (DTD) primarily define?

The structure of the document including tags and attributes Signup and view all the answers

Which of the following statements about external DTDs is correct?

They can be referenced using the SYSTEM or PUBLIC keyword. Signup and view all the answers

What is indicated by the root element in an XML document?

It identifies the starting element of the document. Signup and view all the answers

Which keyword is used to reference an external subset DTD in a DOCTYPE declaration?

SYSTEM Signup and view all the answers

Which type of constraints are defined by a DTD for attributes in an XML document?

Attribute value constraints Signup and view all the answers

Study Notes

CSBP 461 Internet Computing: XML Basics (Part 1)

Course title: CSBP 461 Internet Computing
Course topic: XML Basics (Part 1)
Instructor: Dr. M. Elarbi Badidi
Semester: Fall 2020

Objectives

Introduce XML concepts
Introduce XML description technologies (DTD and XML Schema)

XML Overview

When referring to XML, it typically encompasses XML and related technologies (e.g., XSLT, XOL, SGML, W3C, HTML, SAX, JDOM, DOM).
XML is a meta-language for describing document content (self-describing data).
XML is portable (cross-platform) for encapsulating and describing data.
XML tags are defined by the author, unlike HTML tags which are predefined by W3C standards.

XML Resources

XML 1.0 Specification: http://www.w3.org/TR/REC-xml
WWW Consortium's Home Page on XML: http://www.w3.org/XML/
Apache XML Project: http://xml.apache.org/
XML Resource Collection: http://xml.coverpages.org/xml.html
O'Reilly XML Resource Center: http://www.xml.com/

Simple XML Document (Example)

XML documents typically start with a prolog declaration (e.g., <?xml version="1.0"?>).
The basic structure consists of nested elements with opening and closing tags. (e.g., <tag>data</tag>).

XML Components

Prolog: Defines XML version, entity declarations, and DOCTYPE.
Components of the document: Tags, attributes, CDATA, entities, processing instructions, and comments

XML Overview (continued)

XML documents have a single root element (e.g., <book>.)
Tag names describe data (e.g., <price>).
Additional information can be provided via attributes (e.g., currency="usd").
Applications exchanging XML need a shared understanding of the data represented by descriptive tag names and attributes.
XHTML is an example of HTML restructured to conform to XML rules.

XML Prolog

XML files usually start with a prolog containing the XML version, encoding, and standalone attributes.
The version and encoding are necessary, and the standalone value shows if an external file is referenced for entity/DTD definitions.

XML Elements

XML elements are composed of XML tags and the data they encapsulate (e.g., <price>5.50</price>).
Tag names are case-sensitive.
Tags start with a letter or underscore, followed by numbers or periods.
Tags cannot contain spaces.
Element contents must be character data in the specified encoding.
Elements are completely nested, meaning tag order is significant.
XML elements can have attributes, providing metadata for the element.

XML Elements, continued

Attributes provide metadata about the element's content, properties, or other information.
Every attribute must have a value, even if it's an empty string.
Attributes cannot be repeated within a single element.

XML Comments

Comments start with .
They must not contain consecutive hyphens.
They can be placed anywhere in the document and aren't considered XML elements.

Processing Instructions

Processing instructions start with <? immediately followed by the target name and end with ?> to provide instructions for XML processors.

Document Entities

Entities represent data items, typically text.
General entity references begin with & and end with ;.
Reserved characters (e.g., <, &, ", ', >) require entity references to avoid conflicts with the XML application.
Entities are often user-definable.

Well-Formed versus Valid XML

Well-formed XML means the XML structure matches basic syntax rules.
Valid XML signifies that the structure conforms to the defined rules of a Document Type Definition (DTD).
XML parsers often require more structure than HTML to correctly interpret and handle XML syntax errors.

Document Type Definition (DTD)

Defines the structure of an XML document.
Specifies allowed tags, their attributes, nesting rules, and the number of occurrences.
Entities inside the document are also defined.
A DTD can be external to the XML document (referenced in the DOCTYPE declaration either with SYSTEM or PUBLIC to a specific URI or URL).

XML DOCTYPE

The DOCTYPE declaration specifies the location of the DTD, either internal or by referencing an external resource.
SYSTEM is used for resolving private DTDs and PUBLIC is for those intended for public use.

Defining Elements

<!ELEMENT name definition/type> describes the elements available within a specific element name and type.

Defining Attributes

Used to specify attributes attached to specific xml elements, e.g., <!ATTLIST Product cost CDATA #FIXED "200".

Attribute Types

CDATA specifies any unparsed data.
Enumeration specifies a fixed list of possible attribute values.

Attribute Modifiers

#IMPLIED means the attribute is optional; #REQUIRED means the attribute must be included.
#FIXED specifies a predefined and unchangeable attribute value.

Defining Entities

Defines entities (replacement text) to be referenced in the XML document.

Limitations of DTDs

DTDs are not XML-formatted, hence present more parsing work.
DTDs lack strong data typing (integers, decimals, booleans).
DTDs do not enforce a specific data format.
No namespace support.
Document overrides external DTD definitions.
Lack of DOM support.

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Description

Test your knowledge on fundamental concepts of XML, including well-formedness, attribute values, and syntax rules. This quiz covers essential topics essential for understanding how XML structures data. Perfect for beginners and those looking to refresh their XML skills.