DB2 XQuery concepts
The following topics introduce basic XQuery concepts and
describe how XQuery works with a DB2 database.
Type system
XQuery is a strongly-typed language in which the operands
of various expressions, operators, and functions must conform to expected
types. The type system for DB2 XQuery
includes the built-in types of XML Schema and the predefined types
of XQuery.
Prolog
The prolog is series of declarations that
define the processing environment for a query. Each declaration in
the prolog is followed by a semicolon (;). The prolog is an optional
part of the query; a valid query can consist of a query body with
no prolog.
Expressions
Expressions are the basic building blocks of a query. Expressions
can be used alone or in combination with other expressions to form
complex queries. DB2 XQuery
supports several kinds of expressions for working with XML data.
Built-in functions
DB2 XQuery
provides a library of built-in functions for working with XML data.
These built-in functions include XQuery-defined functions and DB2
built-in functions.
Regular expressions
A regular expression is a sequence
of characters that act as a pattern for matching and manipulating
strings.
Limits
DB2 XQuery has size
limits and limits for data types.
DB2 Version 10.1 for Linux, UNIX, and Windows