EXAMPLE7.C

/*example7.c */ 
/* 
** This example illustrates the use of browse mode functions to 
** determine the source of result columns from ad hoc queries. 
*/ 
 
#if defined(DBNTWIN32) 
#include <windows.h> 
#endif 
 
#include <stdio.h> 
#include <sqlfront.h> 
#include <sqldb.h> 
 
voidexamine_results(); 
BOOL send_command(); 
 
/* Forward declarations of the error-handling and message-handling 
functions. */ 
int err_handler(DBPROCESS*, int, int, int, char*, char*); 
int msg_handler(DBPROCESS*, DBINT, int, int, char*); 
 
main() 
{ 
LOGINREC*login; 
DBPROCESS*dbproc; 
 
intcommand_count = 0; 
RETCODEretcode; 
 
        dbinit();/* initialize dblib */ 
 
/* Install the user-supplied error-handling and message-handling 
* functions. They are defined at the bottom of this source file. 
*/ 
dbmsghandle((DBMSGHANDLE_PROC)msg_handler); 
dberrhandle((DBERRHANDLE_PROC)err_handler); 
 
/* Allocate and initialize the LOGINREC structure to be used 
* to open a connection to SQL Server. 
*/ 
 
login = dblogin(); 
DBSETLUSER(login, "user"); 
DBSETLPWD(login, "my_passwd"); 
DBSETLAPP(login, "example7"); 
DBSETLVERSION(login, DBVER60); 
 
dbproc = dbopen(login, "my_server"); 
 
/* Allow the user to type in a series of queries. This program 
* is terminated by the word "quit" appearing at the 
* beginning of the line. 
*/ 
while (1) 
{ 
// Send a user-generated query to SQL Server. 
// Exit if user typed in quit. 
 
if (!send_command(dbproc)) 
break; 
 
/* Now, examine the results of any queries the user has 
* typed in. 
*/ 
 
command_count = 1; 
while ((retcode = dbresults(dbproc)) != NO_MORE_RESULTS) 
{ 
command_count++ ; 
if (retcode == FAIL) 
printf("Command %d failed.\n", command_count); 
else 
{ 
if (!(DBCMDROW(dbproc))) 
printf 
("Command %d returned no rows.\n", 
command_count); 
else 
{ 
/* This is a command that can return 
* rows. Let's take a closer look at it. 
*/ 
printf("Command %d:\n", command_count); 
examine_results(dbproc); 
 
/* Throw away all data rows. */ 
dbcanquery(dbproc); 
} 
} 
} 
} 
 
return(STDEXIT); 
} 
 
void examine_results(dbproc) 
DBPROCESS*dbproc; 
{ 
intcolcount; 
intcolnum; 
charfullsource[128]; 
const char *sourcecolname; 
inttabcount; 
const char *tabname; 
inttabnum; 
 
/* Determine which tables were used to generate the query results.*/ 
 
tabcount = dbtabcount(dbproc); 
printf 
("The following tables were used to generate these query results:\n"); 
 
for (tabnum = 1; tabnum <= tabcount; tabnum++) 
{ 
if ((tabname = dbtabname(dbproc, tabnum)) != NULL) 
printf 
("\t%s (%s)\n", tabname, 
(dbtabbrowse(dbproc, tabnum) 
? "browsable" : "not browsable")); 
} 
 
/* Determine which tables were used to generate each result column.*/ 
 
colcount = dbnumcols(dbproc); 
printf("Here are the columns of the target list and their sources:\n"); 
 
printf 
("\t%-20s%-30s%s\n\n", 
"Result column:", "Source:", "Browsable?"); 
for (colnum = 1; colnum <= colcount; colnum++) 
{ 
tabname = dbtabsource(dbproc, colnum, NULL); 
sourcecolname = dbcolsource(dbproc, colnum); 
 
if (tabname == NULL) 
strcpy(fullsource, "(result of expression)"); 
else 
sprintf(fullsource, "%s.%s", tabname, sourcecolname); 
 
printf 
("\t%-20s%-30s%s\n", 
dbcolname(dbproc, colnum), 
fullsource, 
(dbcolbrowse(dbproc, colnum) ? "yes" : "no")); 
} 
} 
 
 
BOOL send_command(dbproc) 
DBPROCESS*dbproc; 
{ 
 
static charcmdbuf[2048]; 
 
/* Allow the user to type in an ad hoc query. This query 
* is terminated by the word "go" appearing at the 
* beginning of the line. 
* 
* If the user types the word "quit" at the beginning of a line, 
* we'll quit the program. 
*/ 
printf("Enter SQL query (or 'quit'):\n"); 
 
while (1) 
{ 
printf("> "); 
gets(cmdbuf); 
 
if (strcmp(cmdbuf, "go") == 0) 
{ 
dbsqlexec(dbproc); 
break; 
} 
else if (strcmp(cmdbuf, "quit") == 0) 
{ 
return FALSE; 
} 
else 
{ 
/* Keep reading SQL commands. */ 
dbcmd(dbproc, cmdbuf); 
} 
} 
 
return TRUE; 
} 
 
int err_handler(dbproc, severity, dberr, oserr, dberrstr, oserrstr) 
DBPROCESS*dbproc; 
intseverity; 
intdberr; 
intoserr; 
char*dberrstr; 
char*oserrstr; 
{ 
    printf("DB-LIBRARY error:\n\t%s\n", dberrstr); 
 
if (oserr != DBNOERR) 
printf("Operating-system error:\n\t%s\n", oserrstr); 
 
if ((dbproc == NULL) || (DBDEAD(dbproc))) 
return(INT_EXIT); 
 
return(INT_CANCEL); 
} 
 
int msg_handler(dbproc, msgno, msgstate, severity, msgtext) 
DBPROCESS*dbproc; 
DBINTmsgno; 
intmsgstate; 
intseverity; 
char*msgtext; 
{ 
printf 
("SQL Server message %ld, state %d, severity %d:\n\t%s\n", 
msgno, msgstate, severity, msgtext); 
return(0); 
}