INFORMIX-ESQL/C Programmer's Manual ESQL/C Function Library

The rtypwidth() function returns the minimum number of characters that a character data type needs to avoid truncation when you convert a value with an SQL data type to a character data type.

mint rtypwidth(sqltype,  sqllen)

	mint  sqltype;

	mint  sqllen;

 



sqltype  

is the integer code of the SQL data type. For more information, see Data Type Constants.


sqllen

is the number of bytes in the data file for the specified SQL data type. 

Informix provides the rtypwidth() function for use with the sqlda structure that a DESCRIBE statement initializes. The sqltype and sqllen components correspond to the components of the same name in each sqlda.sqlvar structure.

This sample program is in the rtypwidth.ec file in the demo directory.

/*
* rtypwidth.ec *

This program displays the name of each column in the 'orders' table and
the number of characters required to store the column when the
data type is converted to characters.
*/

#include <stdio.h>

#define WARNNOTIFY 1
#define NOWARNNOTIFY 0

main(argc, argv)
int argc;
char *argv[];
{
mint i, numchars;

int4 exp_chk();
char db_stmnt[50];
struct sqlda *sql_desc;
struct sqlvar_struct *col;

EXEC SQL BEGIN DECLARE SECTION;
char db_name[20];
EXEC SQL END DECLARE SECTION;

printf("RTYPWIDTH Sample ESQL Program running.\n\n");

if (argc > 2) /* correct no. of args? */
{
printf("\nUsage: %s [database]\nIncorrect no. of argument(s)\n",
argv[0]);
exit(1);
}
strcpy(db_name, "stores7");
if (argc == 2)
strcpy(db_name, argv[1]);

EXEC SQL connect to :db_name;
sprintf(db_stmnt, "CONNECT TO %s", argv[1]);
exp_chk(db_stmnt, NOWARNNOTIFY);

printf("Connected to %s\n", db_name);

EXEC SQL prepare query_1 from 'select * from orders'; /* prepare select */
if(exp_chk("Prepare", WARNNOTIFY) == 1)
exit(1);
EXEC SQL describe query_1 into sql_desc; /* setup sqlda */
if(exp_chk("Describe", WARNNOTIFY) == 1)
exit(1);
printf("\n\tColumn Name \t# chars\n");

/*
* For each column in orders print the column name and the minimum
* number of characters required to convert the SQL type to a character
* data type
*/
for (i = 0, col = sql_desc->sqlvar; i < sql_desc->sqld; i++, col++)
{
numchars = rtypwidth(col->sqltype, col->sqllen);
printf("\t%-15s\t%d\n", col->sqlname, numchars);
}

printf("\nRTYPWIDTH Sample Program over.\n\n");
}

/*
* The exp_chk() file contains the exception handling functions to
* check the SQLSTATE status variable to see if an error has occurred
* following an SQL statement. If a warning or an error has
* occurred, exp_chk() executes the GET DIAGNOSTICS statement and
* prints the detail for each exception that is returned.
*/
EXEC SQL include exp_chk.ec

For a complete listing of the exp_chk() function, see Guide to the exp_chk.ec File or refer to the exp_chk.ec file for a listing of this exception-handling function.

RTYPWIDTH Sample ESQL Program running.



Connected to stores7



	Column Name    				# chars

	order_num      				11

	order_date     				10

	customer_num   				11

	ship_instruct  				40

	backlog        				1

	po_num        			 	10

	ship_date     			 	10

	ship_weight    				10

	ship_charge    				9

	paid_date      				10



RTYPWIDTH Sample Program over.