XML XQuery Functions Overview

XQuery functions are pre-defined modules of code that help to streamline the development of XQuery applications. XQuery functions perform a variety of tasks, such as mathematical calculations, string manipulation, and date/time formatting. This page provides an overview of XQuery functions, including their syntax, examples, output, explanation, use cases, important points, and summary.

Syntax

The syntax for XQuery functions is as follows:

function-name(argument1, argument2, ..., argumentN)

where function-name is the name of the function and argument1...argumentN are the input arguments for the function.

Example

Here is an example of how to use the upper-case() function to convert a string to uppercase:

let $myString := "hello world"
return upper-case($myString)

Output: HELLO WORLD

Explanation

The upper-case() function takes a string as input and returns the uppercase equivalent of that string. The let statement is used to set a variable called $myString to the value "hello world". The return statement then passes the $myString variable as an argument to the upper-case() function, which returns the string in all uppercase letters.

Use

XQuery functions can be used in a variety of situations in which a pre-defined module of code is needed. Some common use cases include:

• Mathematical calculations: Functions such as abs(), ceiling(), floor(), round(), and sum() can be used to perform mathematical calculations on numeric data.
• String manipulation: Functions such as substring(), starts-with(), contains(), ends-with(), and replace() can be used to manipulate strings.
• Date/time formatting: Functions such as current-date(), current-time(), current-dateTime(), date(), time(), and dateTime() can be used to format date and time data.

Important Points

When using XQuery functions, it is important to keep the following points in mind:

• XQuery functions are case-sensitive.
• Some functions require a specific input data type, and may return an error if the wrong data type is provided.
• Many XQuery functions are designed to work with other XQuery constructs, such as XPath expressions and variables.

Summary

XQuery functions are pre-defined modules of code that perform a variety of tasks in XQuery applications. They can be used for mathematical calculations, string manipulation, date/time formatting, and more. Important points to keep in mind when using XQuery functions include case-sensitivity, data typing requirements, and their dependence on other XQuery constructs.