以下是我的代码:
#include <sys/types.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <db.h>
#define DATABASE "access.db"
typedef struct {
char data1[20];
char src[20];
} pearson_record;
我收到错误:
指定给DB-&gt; get的非法标志 DB-&gt; get:参数无效
知道我哪里出错了。
int
main()
{
pearson_record s;
char *papa="1.1.1.1";
char *source="papa";
DB *dbp;
DBT key, data;
int ret, t_ret;
db_recno_t recno;
if ((ret = db_create(&dbp, NULL, 0)) != 0) {
fprintf(stderr, "db_create: %s\n", db_strerror(ret));
exit (1);
}
if ((ret = dbp->open(dbp,
NULL, DATABASE, NULL, DB_BTREE, DB_CREATE, 0664)) != 0) {
dbp->err(dbp, ret, "%s", DATABASE);
goto err;
}
recno = 10;
#define BUFFER_LENGTH (5 * 1024 * 1024)
data.ulen = BUFFER_LENGTH;
data.flags = DB_DBT_USERMEM;
strncpy(s.data1, papa, strlen(papa)+1);
strncpy(s.src, source, strlen(source)+1);
memset(&key, 0, sizeof(key));
memset(&data, 0, sizeof(data));
//memset(&s, 0, sizeof(struct pearson_record));
key.data = &recno;
key.size = sizeof(recno);
data.data = &s;
data.size = sizeof(s);
papa="1.1.1.2";
source="papaa";
strncpy(s.data1, papa, strlen(papa)+1);
strncpy(s.src, source, strlen(source)+1);
if ((ret = dbp->put(dbp, NULL, &key,&data,0)) == 0)
printf("db: %d: key stored.\n", *(int *)key.data);
else
{
dbp->err(dbp, ret, "DB->put");
goto err;
}
recno = 11;
strncpy(s.data1, papa, strlen(papa)+1);
strncpy(s.src, source, strlen(source)+1);
memset(&key, 0, sizeof(key));
memset(&data, 0, sizeof(data));
//memset(&s, 0, sizeof(struct pearson_record));
key.data = &recno;
key.size = sizeof(recno);
data.data = &s;
data.size = sizeof(s);
papa="1.1.1.2";
source="papaa";
strncpy(s.data1, papa, strlen(papa)+1);
strncpy(s.src, source, strlen(source)+1);
if ((ret = dbp->put(dbp, NULL, &key,&data,0)) == 0)
printf("db: %d: key stored.\n", *(int *)key.data);
else
{
dbp->err(dbp, ret, "DB->put");
goto err;
}
pearson_record *ppr;
if ((ret = dbp->get(dbp, NULL, &key, &data, DB_SET_RECNO)) == 0) {
ppr = (pearson_record *) data.data;
printf("db: %d: key retrieved: data was %s,%s. %d\n",
*(int *)key.data, ppr->data1,ppr->src, data.size);
}
else {
dbp->err(dbp, ret, "DB->get");
goto err;
}
if ((ret = dbp->get(dbp, NULL, &key, &data, DB_SET_RECNO)) == 0) {
ppr = (pearson_record *) data.data;
printf("db: %d: key retrieved: data was %s,%s. %d\n",
*(int *)key.data, ppr->data1,ppr->src, data.size);
}
else {
dbp->err(dbp, ret, "DB->get");
goto err;
}
err: if ((t_ret = dbp->close(dbp, 0)) != 0 && ret == 0)
ret = t_ret;
exit(ret);
}
答案 0 :(得分:3)
快速浏览一下DB->get的文档说:“要指定DB_SET_RECNO,底层数据库必须是Btree类型,并且必须使用DB_RECNUM标志创建它。”
看起来您没有使用该标志创建数据库。我没有查看其余代码,但这是一个需要修复的明显位置。
您也可以在网上Berkeley DB forum提出这些问题。
问候,
戴夫