Priscilla Walmsley - XQuery: Search Across a Variety of XML Data

• 2015-06-25: First Release

The book is organized into six parts:

1. provide a high-level overview and quick tour of XQuery.

2. provide enough information to write sophisticated queries, without being bogged down by the details of types, namespaces, and schemas.

3. introduce some advanced concepts for users who want to take advantage of modularity, namespaces, typing, and schemas.

4. provide guidelines for working with specific types of data, such as numbers, strings, dates, URIs, processing instructions and maps.

5. describe XQuerys implementation-specific features and its relationship to other standards SQL and XSLT.

6. provide a complete alphabetical reference to the built-in functions, types, and error messages.

illustrates the components of a syntax diagram, showing the schema import syntax as an example.

Figure P-1. Example syntax diagram

Rules for interpreting the syntax diagrams are:

• Parts of the diagram in constant width font are literal values. In , import schema and at should appear literally in your query.

• Quotes that appear in syntax diagrams also must appear in your query. shows that the <namespace-name> must be surrounded by quotes, whereas the <prefix> must not. Either single or double quotes can be used in XQuery, but only double quotes are included in the diagrams for simplicity.

• Where you can specify a value, such as a name, a descriptive name for that value appears in constant width italic and is surrounded by angle brackets. shows that you fill in the <namespace-name>, <prefix>, and <location> with your own values.

• Multiple options are indicated by parallel lines in the diagram. shows that you may choose to specify a namespace prefix or default element namespace.

• Optional parts of the expression are indicated by a line that bypasses the main arrow. In , it is not necessary to include the namespace <prefix> = or the default element namespace keywords.

• Repeating parts of an expression are indicated by an arrow that returns to the beginning. shows that you can specify multiple <location>s (separated by commas) as part of the at clause.

Constant width is used for:

• Code examples and fragments

• Anything that might appear in an XML document, including element and attribute names, element contents, attribute values, and processing instructions

• Anything that might appear in a query, including keywords, operators and literals

Constant width bold is used for:

• Emphasis in code examples and fragments

Italic is used for:

• New terms where they are defined

• Emphasis in body text

• Pathnames, filenames, and program names

• Host and domain names