Question

在Mac上使用sqlite3的内置命令行工具，我在下面运行sql架构（由Lynda.com教程创建）来创建一个sql数据库，数据库bwrss.db显示为已创建在架构所在的下载文件夹中。然后我运行了本教程提供的代码，该代码应该读取并显示创建db时插入的feed ID

-(void) dispRow:(NSDictionary *) row {
    message(@"row %@ [%@]", row [@"title"], row [@"url"]);
}

-(void) testDatabase {
    RSSDB *db;
    NSString * dbfn = @"bwrss.db";

    db = [[RSSDB alloc] initWithRSSDBFilename:dbfn];
    message(@"RSSDB version %@", [db getVersion]);

    for (NSNumber *n in [db getFeedIDs]) {
        NSDictionary *feed = [db getFeedRow:n];
        [self dispRow:feed];
    }
}

但是，当我运行代码时，它只显示版本号（来自testDatabase方法的第4行），但没有其他内容。它在xCode控制台中显示此错误。

2014-03-21 10:00:51.052 Testbed[1381:a0b] bindSQL: could not prepare statement (no such table: main.feed) CREATE UNIQUE INDEX IF NOT EXISTS feedUrl ON feed(url)
2014-03-21 10:00:51.056 Testbed[1381:a0b] bindSQL: could not prepare statement (no such table: feed) SELECT id FROM feed ORDER BY LOWER(title)
2014-03-21 10:00:51.058 Testbed[1381:a0b] rowFromPreparedQuery: could not get row: no such table: feed

Lynda.com讲师说，如果它只显示版本，则意味着您可能必须从模拟器中删除应用程序以便加载新数据，因为我们在前面的部分中创建了多个版本的应用程序。

错误消息显示，＆＃34;没有这样的表：feed＆＃34;但数据库显示为已创建。你能解释一下为什么会这样吗？ db文件与项目不在同一个目录中，但我的理解是它不是必须的。

模式

-- bwrss.sql
-- by Bill Weinman - http://bw.org/contact/
-- SQLite database for BW RSS iOS app
-- Copyright 2009-2010 The BearHeart Group LLC

-- This script creates the database tables for the BW RSS application
-- and seeds the feed table with initial records. 

DROP TABLE IF EXISTS feed;
DROP TABLE IF EXISTS item;

CREATE TABLE feed (
    id      INTEGER PRIMARY KEY,    -- unique id for this record
    url     TEXT,                   -- url for data
    title   TEXT,                   -- title of the feed
    desc    TEXT,                   -- description of the feed
    pubdate TEXT,                   -- feed last update date/time
    stamp   TEXT DEFAULT CURRENT_TIMESTAMP
);
CREATE TABLE item (
    id      INTEGER PRIMARY KEY,    -- unique id for this record
    feed_id INTEGER,                -- feed id
    url     TEXT,                   -- url of item
    title   TEXT,                   -- title of the item
    desc    TEXT,                   -- description of the item
    pubdate TEXT,                   -- publication date/time of this item
    stamp   TEXT DEFAULT CURRENT_TIMESTAMP
);

CREATE UNIQUE INDEX feedUrl ON feed(url);

INSERT INTO feed (url, title, desc) VALUES (
    'http://feeds.feedburner.com/lyndablog',
    'lynda.blog',
    'the blog of lynda.com'
);

INSERT INTO feed (url, title, desc) VALUES (
    'http://feeds.feedburner.com/lyndacom-new-releases',
    'lynda.com New Releases',
    'lynda.com New Releases RSS Feed.'
);

INSERT INTO feed (url, title, desc) VALUES (
    'http://billweinman.wordpress.com/feed/',
    'Bill Weinman''s Technology Blog',
    'because it''s all about the data'
);

Answer 1

如果我在ios模拟器中打开，我会遇到同样的问题。

2014-10-23 00:47:34.166 RSS[10465:544566] bindSQL: could not prepare statement (no such table: main.feed) CREATE UNIQUE INDEX IF NOT EXISTS feedUrl ON feed(url)
2014-10-23 00:47:34.167 RSS[10465:544566] bindSQL: could not prepare statement (no such table: feed) SELECT id FROM feed ORDER BY LOWER(title)
2014-10-23 00:47:34.167 RSS[10465:544566] rowFromPreparedQuery: could not get row: no such table: feed
2014-10-23 00:47:34.167 RSS[10465:544566] bindSQL: could not prepare statement (no such table: feed) SELECT id FROM feed ORDER BY LOWER(title)
2014-10-23 00:47:34.167 RSS[10465:544566] rowFromPreparedQuery: could not get row: no such table: feed
2014-10-23 00:47:34.168 RSS[10465:544566] bindSQL: could not prepare statement (no such table: feed) SELECT id FROM feed ORDER BY LOWER(title)
2014-10-23 00:47:34.168 RSS[10465:544566] rowFromPreparedQuery: could not get row: no such table: feed
2014-10-23 00:47:34.169 RSS[10465:544566] bindSQL: could not prepare statement (no such table: feed) SELECT id FROM feed ORDER BY LOWER(title)
2014-10-23 00:47:34.169 RSS[10465:544566] rowFromPreparedQuery: could not get row: no such table: feed

但在正常的设备中工作

也许这就是方法中的原因：

BWDB.m / - （NSNumber *）insertRow：（NSDictionary *）record
BWDB.m / - （void）updateRow：（NSDictionary *）recordforRowID：（NSNumber *）rowID

[self bindSQL:[query UTF8String] withVargs:(va_list)dValues.mutableBytes];

错误：

.../BWDB/BWDB.m:276:48: Used type 'va_list' (aka '__builtin_va_list') where arithmetic or pointer type is required

已创建sqlite3数据库，但表不存在

1 个答案: