Dbkexpr()

PURPOSE

get key expression

SYNOPSIS

#include "dbl.h"
 
	int	dbkexpr(ndx, keytype, keyexpr, keyprlen, keylen)
 
	<input parameters>
	char	*ndx;		/* .NDX file descriptor		*/
 
	<output parameters>
	char	keytype;	/* Index key data type:
				   'C' – CHARACTER
				   'N' – NUMERIC
				   'D' – DATE*/
	char	*keyexpr;	/* Index key expression		*/
	int	*kexprlen;	/* Length of index key expression	*/
	int	*keylen;	/* Index key length			*/

RETURN VALUE

The dbkexpr() function returns 0 for success, or < 0 if an error occurs. See the section on return code values for a detailed list of return codes.

DESCRIPTION

This function obtains the index information from the specified .NDX file. This information includes:

• index key data type('C' for CHARACTER keys, 'N' for NUMERIC and 'D' for DATE),
• index key expression (usually a character string consisting of one or more record field names)
• length of the index key expression
• length of the key.

EXAMPLE

This example obtains the index information from the .NDX file whose file descriptor is in "char *ndx" and prints this information on standard output.

#include "dbl.h"
 
	char	*ndx;			/* .NDX file descriptor	*/
	char	keytype;		/* Key type			*/
	char	keyexpr[512];		/* Index key expression	*/
	int	keyexprlen;		/* Expression length		*/
	int	keylen;			/* Key length			*/
	int	rc;			/* Return code			*/
 
	rc = dbkexpr(ndx, &keytype, keyexpr, &keyexprlen,
		&keylen);
	if (rc = = SUCCESS){
		printf("t Index file information - n");
		printf("t t type = '%c', keyexpression = '%s',
			exprlen = %d, keylen = %d n". keytype,
				keyexpr, keyexprlen, keylen);
	} else {
		printf("error number %d n", rc);
		exit (1);
	}

SEE ALSO

dbicreat(), dbkeytoa()