SQL/MX 3.2.1 Programming Manual for C and COBOL (H06.26+, J06.15+)

Host Variables in C/C++ Programs

HP NonStop SQL/MX Release 3.2.1 Programming Manual for C and COBOL—663854-005

3-15

Specifying Host Variables in SQL Statements

Example

The following example shows that you cannot declare a character data type as a host

variable:

EXEC SQL BEGIN DECLARE SECTION;

/* cannot declare a character type pointer as host variable */

char * charPtr;

...

This is an illegal construct and returns the following warnings when compiled:

Hewlett-Packard NonStop(TM) SQL/MX C/C++ Preprocessor 3.2.1

Company, LP.

*** WARNING[13029] Pointer or Reference types not supported for

Host Variables.

*** WARNING[13025] Warning(s) near line 5.

The following example shows the use of character data type in a structure:

EXEC SQL BEGIN DECLARE SECTION;

struct ptrType

{

/* all data types are allowed as structure fields */

char charField[100];

...

};

struct ptrType * structPtr;

...

Specifying Host Variables in SQL Statements

Use host language naming conventions for your host variable and indicator variable

names. For example, a name in a C program contains alphanumeric characters,

including the underscore (_), and begins with a letter or an underscore. To avoid

conflicts with system-generated names, do not begin your host variable names with

underscores.

After you declare a host variable, to specify it within an embedded SQL statement, use

this syntax:

variable-name

is the host variable name. It can be any valid host language identifier with a data

type that corresponds to an SQL data type. You must precede variable-name

with a colon (:) within an SQL statement.

:variable-name [[INDICATOR] :indicator_variable]