iphone - iOS:Sqlite 数据库错误:由于未捕获的异常 'NSInternalInconsistencyException' 而终止应用程序，原因: 'error preparing statement'

Question

我在我的应用程序中使用了 sqlite DB，我需要调用两个同时查询，但我给出的错误为:由于未捕获的异常“NSInternalInconsistencyException”而终止应用程序，原因:“准备语句时出错”

我每 10 秒运行一个计时器，用于在按钮事件后从数据库中选择行和在数据库中插入行。

我的代码片段为:

在viewWillAppear中:

int result2 = sqlite3_open([dbPath UTF8String], &database);
if (result2 != SQLITE_OK) {
    NSLog(@"Failure in connecting to the database with result %d",result2);
}
else {
    NSLog(@ "Succesfully opened connection to DB") ;

}

并在viewWillDisappear中:

int result = sqlite3_close(database);
if (result != SQLITE_OK){
    NSLog(@"Failure in closing connection to database. Result %d",result);
}
else {
    NSLog(@"Successfully closed DB connection") ;
}

对于插入行:

NSString *queryInsert = [NSString stringWithFormat: @"insert into mail_snoozlist (msgBody,msgSubject, msgSender,msgTo,msgDate,snoozTime) values('%@','%@','%@','%@','%@','%@')",strBody,msgSub,msgFrom,msgTo,strMsgDate,stringFromDate];

    NSLog(@"queryInsert:%@",queryInsert);

    const char *sql = [queryInsert UTF8String];

    if(sqlite3_prepare_v2(database, sql, -1, &statement, NULL) == SQLITE_OK) {
        sqlite3_step(statement);
        sqlite3_reset(statement);

    } else {

        NSAssert1(0,@"error preparing statement",sqlite3_errmsg(database));
        return;
    }

    sqlite3_finalize(statement);

以及选择行:

NSString *querySQL2 = [NSString stringWithFormat: @"Select * from mail_snoozlist WHERE snoozTime = '%@'",_snoozTime];

    NSLog(@"querySql:%@",querySQL2);

    if (sqlite3_prepare_v2(database, [querySQL2 UTF8String], -1, &statement, NULL) == SQLITE_OK)
    {

        while (sqlite3_step(statement) == SQLITE_ROW)
        {
            Message *obj = [[Message alloc] init];

            NSString *msgBody=[[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 1)];
            obj.msgBody= msgBody;

            NSString *msgSub=[[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 2)];
            obj.msgSub= msgSub;

            NSString *msgSender=[[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 3)];
            obj.msgFrom= msgSender;

            NSString *msgTo=[[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 4)];
            obj.msgTo= msgTo;

            NSString *msgDate=[[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 5)];
            obj.msgDate= msgDate;

            [listOfItems addObject:obj];

            [self.tableView reloadData];
        }

        sqlite3_reset(statement);
        sqlite3_finalize(statement);

请大家帮我解决一下这个问题。

谢谢!

Answer 1

您应该更改您的 NSAssert 语句以包含错误消息:

NSAssert1(0, @"error preparing statement: %s", sqlite3_errmsg(database));

一旦您这样做，您应该会得到有意义的响应，这将帮助您诊断问题。

如果不查看sqlite3_errmsg消息，就很难诊断问题。它可能像列名或表名中的拼写错误一样简单，也可能像由于创建数据库时未找到而找不到表一样复杂，因此创建了一个空白数据库(没有该表)。在我们看到错误消息之前很难说。

---

顺便说一句，您不应该使用 stringWithFormat 构建 SQL，因为您容易遭受 SQL 注入(inject)攻击，并且如果这些文本值中的任何一个包含撇号，也会出现问题。您应该使用 ? 占位符而不是 printf 样式的格式化程序，然后使用 sqlite3_bind_text 调用将值绑定(bind)到这些列:

NSString *queryInsert = @"insert into mail_snoozlist (msgBody,msgSubject, msgSender,msgTo,msgDate,snoozTime) values(?, ?, ?, ?, ?, ?)";

if (sqlite3_prepare_v2(database, sql, -1, &statement, NULL) != SQLITE_OK) {
    NSAssert1(0,@"error preparing statement: %s",sqlite3_errmsg(database));
    return;
}

// for these 6 sqlite3_bind function calls, if any of these strings can be `nil`, then you'd
// want to call sqlite3_bind_null if that's the case, rather than sqlite3_bind_text

if (sqlite3_bind_text(statement, 1, [strBody UTF8String], -1, NULL) != SQLITE_OK) {
    NSAssert1(0,@"error binding 1: %s",sqlite3_errmsg(database));
    sqlite3_finalize(statement);
    return;
}

if (sqlite3_bind_text(statement, 2, [msgSub UTF8String], -1, NULL) != SQLITE_OK) {
    NSAssert1(0,@"error binding 2: %s",sqlite3_errmsg(database));
    sqlite3_finalize(statement);
    return;
}

if (sqlite3_bind_text(statement, 3, [msgFrom UTF8String], -1, NULL) != SQLITE_OK) {
    NSAssert1(0,@"error binding 3: %s",sqlite3_errmsg(database));
    sqlite3_finalize(statement);
    return;
}

if (sqlite3_bind_text(statement, 4, [msgTo UTF8String], -1, NULL) != SQLITE_OK) {
    NSAssert1(0,@"error binding 4: %s",sqlite3_errmsg(database));
    sqlite3_finalize(statement);
    return;
}

if (sqlite3_bind_text(statement, 5, [strMsgDate UTF8String], -1, NULL) != SQLITE_OK) {
    NSAssert1(0,@"error binding 5: %s",sqlite3_errmsg(database));
    sqlite3_finalize(statement);
    return;
}

if (sqlite3_bind_text(statement, 6, [stringFromDate UTF8String], -1, NULL) != SQLITE_OK) {
    NSAssert1(0,@"error binding 6: %s",sqlite3_errmsg(database));
    sqlite3_finalize(statement);
    return;
}

if (sqlite3_step(statement) != SQLITE_DONE) {
    NSAssert1(0,@"error stepping: %s",sqlite3_errmsg(database));
}

sqlite3_finalize(statement);

我用 insert 语句说明了这个问题，但同样也应该用 select 语句来完成。