Viewing file:  example_database_read.c (7.38 KB) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
/* File: example_database_read.c */
/* We assume an ANSI-compatible compiler */
#include "gettingstarted_common.h"
/* Forward declarations */
int usage(void);
char *show_inventory_item(void *);
int show_all_records(STOCK_DBS *);
int show_records(STOCK_DBS *, char *);
int show_vendor_record(char *, DB *);
int
usage()
{
fprintf(stderr, "example_database_read [-i <item name>]");
fprintf(stderr, " [-h <database home>]\n");
fprintf(stderr,
"\tNote: Any path specified to the -h parameter must end\n");
fprintf(stderr, " with your system's path delimiter (/ or \\)\n");
return (-1);
}
/*
* Searches for a inventory item based on that item's name. The search is
* performed using the item name secondary database. Displays all
* inventory items that use the specified name, as well as the vendor
* associated with that inventory item.
*
* If no item name is provided, then all inventory items are displayed.
*/
int
main(int argc, char *argv[])
{
STOCK_DBS my_stock;
int ch, ret;
char *itemname;
/* Initialize the STOCK_DBS struct */
initialize_stockdbs(&my_stock);
/* Parse the command line arguments */
itemname = NULL;
while ((ch = getopt(argc, argv, "h:i:?")) != EOF)
switch (ch) {
case 'h':
if (optarg[strlen(optarg)-1] != '/' &&
optarg[strlen(optarg)-1] != '\\')
return (usage());
my_stock.db_home_dir = optarg;
break;
case 'i':
itemname = optarg;
break;
case '?':
default:
return (usage());
}
/* Identify the files that hold our databases */
set_db_filenames(&my_stock);
/* Open all databases */
ret = databases_setup(&my_stock, "example_database_read", stderr);
if (ret != 0) {
fprintf(stderr, "Error opening databases\n");
databases_close(&my_stock);
return (ret);
}
if (itemname == NULL)
ret = show_all_records(&my_stock);
else
ret = show_records(&my_stock, itemname);
/* close our databases */
databases_close(&my_stock);
return (ret);
}
int show_all_records(STOCK_DBS *my_stock)
{
DBC *inventory_cursorp;
DBT key, data;
char *the_vendor;
int exit_value, ret;
/* Initialize our DBTs. */
memset(&key, 0, sizeof(DBT));
memset(&data, 0, sizeof(DBT));
/* Get a cursor to the inventory db */
my_stock->inventory_dbp->cursor(my_stock->inventory_dbp, NULL,
&inventory_cursorp, 0);
/*
* Iterate over the inventory database, from the first record
* to the last, displaying each in turn.
*/
exit_value = 0;
while ((ret =
inventory_cursorp->c_get(inventory_cursorp, &key, &data, DB_NEXT)) == 0)
{
the_vendor = show_inventory_item(data.data);
ret = show_vendor_record(the_vendor, my_stock->vendor_dbp);
if (ret) {
exit_value = ret;
break;
}
}
/* Close the cursor */
inventory_cursorp->c_close(inventory_cursorp);
return (exit_value);
}
/*
* Search for an inventory item given its name (using the inventory item
* secondary database) and display that record and any duplicates that may
* exist.
*/
int
show_records(STOCK_DBS *my_stock, char *itemname)
{
DBC *itemname_cursorp;
DBT key, data;
char *the_vendor;
int ret, exit_value;
/* Initialize our DBTs. */
memset(&key, 0, sizeof(DBT));
memset(&data, 0, sizeof(DBT));
/* Get a cursor to the itemname db */
my_stock->itemname_sdbp->cursor(my_stock->itemname_sdbp, NULL,
&itemname_cursorp, 0);
/*
* Get the search key. This is the name on the inventory
* record that we want to examine.
*/
key.data = itemname;
key.size = (strlen(itemname) + 1) * sizeof(char);
/*
* Position our cursor to the first record in the secondary
* database that has the appropriate key.
*/
exit_value = 0;
ret = itemname_cursorp->c_get(itemname_cursorp, &key, &data, DB_SET);
if (!ret) {
do {
/*
* Show the inventory record and the vendor responsible
* for this inventory item.
*/
the_vendor = show_inventory_item(data.data);
ret = show_vendor_record(the_vendor, my_stock->vendor_dbp);
if (ret) {
exit_value = ret;
break;
}
/*
* Our secondary allows duplicates, so we need to loop over
* the next duplicate records and show them all. This is done
* because an inventory item's name is not a unique value.
*/
} while (itemname_cursorp->c_get(itemname_cursorp, &key, &data,
DB_NEXT_DUP) == 0);
} else {
printf("No records found for '%s'\n", itemname);
}
/* Close the cursor */
itemname_cursorp->c_close(itemname_cursorp);
return (exit_value);
}
/*
* Shows an inventory item. How we retrieve the inventory
* item values from the provided buffer is strictly dependent
* on the order that those items were originally stored in the
* DBT. See load_inventory_database in example_database_load
* for how this was done.
*/
char *
show_inventory_item(void *vBuf)
{
float price;
int buf_pos, quantity;
char *category, *name, *sku, *vendor_name;
char *buf = (char *)vBuf;
price = *((float *)buf);
buf_pos = sizeof(float);
quantity = *((int *)(buf + buf_pos));
buf_pos += sizeof(int);
name = buf + buf_pos;
buf_pos += strlen(name) + 1;
sku = buf + buf_pos;
buf_pos += strlen(sku) + 1;
category = buf + buf_pos;
buf_pos += strlen(category) + 1;
vendor_name = buf + buf_pos;
printf("name: %s\n", name);
printf("\tSKU: %s\n", sku);
printf("\tCategory: %s\n", category);
printf("\tPrice: %.2f\n", price);
printf("\tQuantity: %i\n", quantity);
printf("\tVendor:\n");
return (vendor_name);
}
/*
* Shows a vendor record. Each vendor record is an instance of
* a vendor structure. See load_vendor_database() in
* example_database_load for how this structure was originally
* put into the database.
*/
int
show_vendor_record(char *vendor_name, DB *vendor_dbp)
{
DBT key, data;
VENDOR my_vendor;
int ret;
/* Zero our DBTs */
memset(&key, 0, sizeof(DBT));
memset(&data, 0, sizeof(DBT));
/* Set the search key to the vendor's name */
key.data = vendor_name;
key.size = strlen(vendor_name) + 1;
/*
* Make sure we use the memory we set aside for the VENDOR
* structure rather than the memory that DB allocates.
* Some systems may require structures to be aligned in memory
* in a specific way, and DB may not get it right.
*/
data.data = &my_vendor;
data.ulen = sizeof(VENDOR);
data.flags = DB_DBT_USERMEM;
/* Get the record */
ret = vendor_dbp->get(vendor_dbp, NULL, &key, &data, 0);
if (ret != 0) {
vendor_dbp->err(vendor_dbp, ret, "Error searching for vendor: '%s'",
vendor_name);
return (ret);
} else {
printf("\t\t%s\n", my_vendor.name);
printf("\t\t%s\n", my_vendor.street);
printf("\t\t%s, %s\n", my_vendor.city, my_vendor.state);
printf("\t\t%s\n\n", my_vendor.zipcode);
printf("\t\t%s\n\n", my_vendor.phone_number);
printf("\t\tContact: %s\n", my_vendor.sales_rep);
printf("\t\t%s\n", my_vendor.sales_rep_phone);
}
return (0);
}
|