INFORMIX
INFORMIX-GLS Programmer's Guide
Introduction
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Documentation Conventions

 This section describes the conventions that this manual uses. These conventions make it easier to gather information from this and other Informix manuals.

The following conventions are covered:

Typographical Conventions

This manual uses the following standard set of conventions to introduce new terms, illustrate screen displays, describe command syntax, and so forth.

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Convention Meaning

KEYWORD

All keywords appear in uppercase letters in a serif font.

italics

Within text, new terms and emphasized words appear in italics. Within syntax diagrams, values that you are to specify appear in italics.

boldface

Identifiers (names of classes, objects, constants, events, functions, program variables, forms, labels, and reports), environment variables, database names, filenames, table names, column names, icons, menu items, command names, and other similar terms appear in boldface.

monospace

Information that the product displays and information that you enter appear in a monospace typeface.

KEYSTROKE

Keys that you are to press appear in uppercase letters in a sans serif font.

This symbol indicates the end of feature-, product-, platform-, or compliance-specific information.

This symbol indicates a menu item. For example, "Choose ToolsOptions" means choose the Options item from the Tools menu.

Tip: When you are instructed to "enter" characters or to "execute" a command, immediately press RETURN after the entry. When you are instructed to "type" the text or to "press" other keys, no RETURN is required.

Icon Conventions

Throughout the documentation, you will find text that is identified by several different types of icons. This section describes these icons.

Comment Icons

Comment icons identify warnings, important notes, or tips. This information is always displayed in italics.

Icon Description

The warning icon identifies vital instructions, cautions, or critical information.

The important icon identifies significant information about the feature or operation that is being described.

The tip icon identifies additional details or shortcuts for the functionality that is being described.

Feature, Product, and Platform Icons

Feature, product, and platform icons identify paragraphs that contain feature-, product-, or platform-specific information.

Icon Description

Identifies information that is specific to the DataBlade API.

Identifies information that is specific to the Informix Global Language Support (GLS) feature.

Identifies information that is specific to INFORMIX-Universal Server.

Identifies information that is specific to INFORMIX-OnLine Dynamic Server.

Identifies information that is specific to INFORMIX-OnLine Workgroup Server.

Identifies information that is specific to INFORMIX-SE.

Identifies information that is specific to the UNIX operating system.

Identifies information that is specific to the Windows NT environment.

Identifies information that is specific to the Windows 95 environment.

Identifies information that is specific to both Windows NT and Windows 95 environments.

Identifies information that is specific to INFORMIX-OnLine XPS.

These icons can apply to a row in a table, one or more paragraphs, or an entire section. A symbol indicates the end of the feature-, product-, or platform-specific information.

Character-Representation Conventions

Throughout this manual, examples show how single-byte and multibyte characters appear. Because multibyte characters are usually ideographic (such as Japanese or Chinese characters), this manual does not use the actual multibyte characters. Instead, it uses ASCII characters to represent both single-byte and multibyte characters. This section provides general information about how this manual represents multibyte and single-byte characters abstractly.

Single-Byte Characters

This manual represents single-byte characters as a series of lowercase letters. The format for representing one single-byte character abstractly is:

In this format, a stands for any single-byte character, not for the letter "a" itself.

The format for representing a string of single-byte characters is as follows:

In this format, a stands for the first character in the string, and z stands for the last character in the string. For example, if the string Ludwig consists of single-byte characters, the following format represents this 6-character string abstractly:

Tip: The letter "s" does not appear in alphabetical sequences that represent strings of single-byte characters. The manual reserves the letter "s" as a symbol that represents a single-byte white-space character. For further information, see "White Space in Strings".

Multibyte Characters

 This manual does not attempt to show the actual appearance of multibyte characters in text, examples, or diagrams. Instead, the following convention shows abstractly how multibyte characters are stored:

One to four identical uppercase letters, each followed by a different superscript number, represent one multibyte character. The superscripts show the first to the nth byte of the multibyte character, where n has values between two and four. For example, the following symbols represent a multibyte character that consists of two bytes:

The following notation represents a multibyte character that consists of four bytes (the maximum length of a multibyte character):

The following example shows a string of multibyte characters in an SQL statement:

This statement creates a database whose name consists of five multibyte characters, each of which is two bytes long. For more information on how to use multibyte characters in SQL identifiers, see the Informix Guide to GLS Functionality.

Single-Byte and Multibyte Characters in the Same String

If you are using a multibyte code set, a given string might be composed of both single-byte and multibyte characters. To represent these mixed strings, this manual simply combines the formats for multibyte and single-byte characters.

For example, suppose that you have a string with four characters. The first and fourth characters are single-byte characters while the second and third characters are multibyte characters that consist of two bytes each. The following format represents this string:

White Space in Strings

 White space is a series of one or more space characters. A GLS locale defines what characters are considered to be space characters. For example, both the TAB and blank might be defined as space characters in one locale, but certain combinations of the CTRL key and another character might be defined as space characters in a different locale.

The convention for representing single-byte white spaces in this manual is the letter "s." The following notation represents one single-byte white space:

In the ASCII code set, an example of a single-byte white space is the blank character (ASCII code number 32). To represent a string that consists of two ASCII blank characters, the manual uses the following notation:

The following notation represents a multibyte white-space character:

In this format s1 represents the first byte of the white-space character, while sn represents the last byte of the white-space character, where n has values between two and four. For example, the following notation represents one 4-byte white-space character:

Trailing White Spaces

 Combinations of characters and white spaces can occur in quoted strings, in CHAR columns that contain fewer characters than the defined length of the column, and in other situations. For example, if a CHAR(5) column in a single-byte code set contains a string of three characters, the string is extended with two white spaces so that its length is equal to the defined length of the column, as follows:

The following example shows the representation for a string of five characters (three characters of data and two trailing white spaces) in a multibyte code set where each of the characters and white-space characters consists of two bytes:

Sometimes a string can contain both single-byte and multibyte white-space characters. In the following example, the string is composed of these elements: three single-byte characters (abc), a single-byte white-space character (s), a multibyte white-space character (s1s2), two single-byte white-space characters (ss), and one multibyte white-space character (s1s2):



INFORMIX-GLS Programmer's Guide, version 9.1
Copyright © 1998, Informix Software, Inc. All rights reserved.