Informix Guide to GLS Functionality

Informix Guide to GLS Functionality
Chapter 8: INFORMIX-ESQL/C Features

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Locale-Sensitive Character Data Types

The SQL data types NCHAR and NVARCHAR support locale-specific data. (For more information about these data types, see "Using Character Data Types".)

ESQL/C supports the predefined data types string, fixchar, and varchar for host variables that contain character data. In addition, you can use the C char data type for host variables. The following table shows which of these host-variable data types you can use for NCHAR and NVARCHAR data.

Locale-Sensitive Data Type char

fixchar

string

varchar

NCHAR
3

3

3

3

NVARCHAR
3

3

3

Tip: For general information on how to use these host-variable data types with character data, see Chapter 3 of the "INFORMIX-ESQL/C Programmer's Manual."

Your ESQL/C program can access columns of data types NCHAR and NVARCHAR when it selects into or reads from character host variables. The following code fragment declares a char host variable, hôte, and then selects NCHAR data into the hôte variable:

/*

	This code fragment declares a char host variable "hôte",

	which contains a non-ASCII character in the name, and

	selects NCHAR data (non-ASCII names in the "nom" column

	of the "abonnés" table) into it.

*/



EXEC SQL BEGIN DECLARE SECTION;

	char hôte[10];
	.

	.

	.


EXEC SQL END DECLARE SECTION;
.

.

.


EXEC SQL select nom into :hôte from abonnés

	where numéro > 13601;

When you declare ESQL/C host variables for the NCHAR and NVARCHAR data types, keep in mind the relationship between the declared size of the variable and the amount of character data that it can hold, as follows:

If your locale supports a single-byte code set, the size of the NCHAR and NVARCHAR variable determines the number of characters that it can hold.
If your locale supports a multibyte code set, you can no longer assume a "one-byte-per-character" relationship.

In this case, you must ensure that you declare an ESQL/C host variable large enough to accommodate the number of characters that you expect to receive from the database.

For more information, see "The NCHAR Data Type" and "The NVARCHAR Data Type".

You can insert a value that a character host variable (char, fixchar, string, or varchar) holds in columns of the NCHAR or NVARCHAR data types. For more information about how to insert host variables into the NCHAR and NVARCHAR data types, see Chapter 3 of the INFORMIX-ESQL/C Programmer's Manual.

Informix Guide to GLS FunctionalityChapter 8: INFORMIX-ESQL/C Features Home Contents Index Master Index New Book

Locale-Sensitive Character Data Types

Informix Guide to GLS Functionality
Chapter 8: INFORMIX-ESQL/C Features

Home Contents Index Master Index New Book