问题描述
我正在尝试在运行时通过 Objective-C 创建一个 SQLite3 数据库文件.我正在尝试创建一个名为tblStore"的表.我希望将字段名称称为strStoreNumber"和strStoreReg".我是 iOS 和 SQLite 的新手,所以我很难找到执行此操作的语法.除了创建表之外,我希望创建的表不驻留在应用程序包中,而是驻留在/存储在手机上的某个地方.该表需要可读/可写.我已经阅读了用户沙箱"和文档目录".我不确定我是否理解两者之间的区别.理想情况下,我的应用程序将使用一个按钮从文本字段中获取输入.将来自文本字段的输入放入字符串后,将进行检查以查看我的tblStore"SQLite 表是否存在,如果不存在,则将创建该表.
I'm trying to create an SQLite3 database file through Objective-C at run time. I am trying to create a table called "tblStore". I want the field names to be called "strStoreNumber" and "strStoreReg". I'm new to iOS and SQLite, so I'm having a hard time finding the syntax to perform this. In addition to creating the table, I want the created table to reside NOT in the app bundle, but rather it would reside/be stored somewhere on the phone. The table needs to be readable/writeable. I've done some reading on "user sandbox" and also a "documents directory". I'm not sure I understand the difference between the two. Ideally, my app would use a button to take input from Text Fields. After the input from the texts fields is put into strings, a check would be done to see if my "tblStore" SQLite table exists, and if it doesn't, the table will be created.
回顾一下:1. Obj-C/SQLite 创建名为tblStore"的表的语法是什么,其中包含strStoreNumber"和strStoreReg"字段?2. db 文件应该放在哪里?我需要读取和写入 tblStore db 文件.3.用户沙箱"和文档目录"有什么区别?
To recap:1. What is the syntax for Obj-C/SQLite to create a table called "tblStore" with the fields "strStoreNumber" and "strStoreReg"?2. Where should the db file reside? I need to read from and write to the tblStore db file.3. What is the difference between a "user sandbox" and a "documents directory"?
这是我目前拥有的:
-(IBAction)setInput:(id)sender
{
NSString *strStoreNumber;
NSString *strRegNumber;
NSString *tableName = @"tblStore";
NSString *dbStrStore = @"strStore";
NSString *dbStrReg = @"strReg";
strStoreNumber = StoreNumber.text;
strRegNumber = RegNumber.text;
NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString* documentsDirectory = [paths lastObject];
NSString* databasePath = [documentsDirectory stringByAppendingPathComponent:@"tblStore.sqlite"];
// NSString* databasePath = [[NSBundle mainBundle] pathForResource:@"tblStore" ofType:@"sqlite"];
if(sqlite3_open([databasePath UTF8String], &database) == SQLITE_OK)
{
NSLog(@"Opened sqlite database at %@", databasePath);
char *err;
NSString *sql = [NSString stringWithFormat:@"CREATE TABLE IF NOT EXISTS '%@' ('%@' TEXT PRIMARY KEY, '%@' TEXT);", tableName, dbStrStore, dbStrReg];
if (sqlite3_exec(database, [sql UTF8String], NULL, NULL, &err) != SQLITE_OK)
{
sqlite3_close(database);
NSAssert(0, @"Table failed to create.");
}
//...stuff
}
else
{
NSLog(@"Failed to open database at %@ with error %s", databasePath, sqlite3_errmsg(database));
sqlite3_close (database);
}
NSString *querystring;
// create your statement
querystring = [NSString stringWithFormat:@"SELECT strStore, strReg FROM tblStore WHERE strStore = %@ AND strReg = %@;", strStoreNumber, strRegNumber];
const char *sql = [querystring UTF8String];
NSString *szStore = nil;
NSString *szReg = nil;
sqlite3_stmt *statement = nil;
if (sqlite3_prepare_v2(database, sql, -1, &statement, NULL)!=SQLITE_OK) //queryString = Statement
{
NSLog(@"sql problem occured with: %s", sql);
NSLog(@"%s", sqlite3_errmsg(database));
}
else
{
// you could handle multiple rows here
while (sqlite3_step(statement) == SQLITE_ROW)
{
szStore = [NSString stringWithUTF8String:(char*)sqlite3_column_text(statement, 0)];
szReg = [NSString stringWithUTF8String:(char*)sqlite3_column_text(statement, 1)];
}
}
sqlite3_finalize(statement);
lblStoreNumber.text = szStore;
lblRegNumber.text = szReg;
}
当我运行我的应用程序时,我收到以下错误:
When I run my app, I get the following errors:
2012-05-10 14:58:38.169 CCoDBTry[355:f803] Opened sqlite database at /Users/Matt****/Library/Application Support/iPhone Simulator/5.1/Applications/5DB7A218-A0F6- 485F-B366-91FD2F9BC062/Documents/tblStore.sqlite
2012-05-10 14:58:38.307 CCoDBTry[355:f803] sql problem occured with: SELECT strStore, strReg FROM tblStore WHERE strStore = 8053 AND strReg = 4;
2012-05-10 14:58:38.308 CCoDBTry[355:f803] no such column: strStore
我感谢任何花时间解释其中一些内容的人,因为我很新,并且在完成我尝试过的一些事情时没有成功.非常感谢您的帮助!
I appreciate anyone who takes the time out to explain some of this stuff, as I am very new and have been unsuccessful in accomplishing some of the things I've tried. Thanks so much for the help!
推荐答案
如果您不知道自己在做什么,sqlite 会很痛苦.我在使用 sqlite c 函数时也遇到了一些问题,但后来我决定使用 sqlite 包装器.
sqlite is a pain if you dont know what you're doing. I also had some problems with sqlite c functions but then i decided to use sqlite wrapper.
FMDB 和 BWDB 是用于目标 c 的良好且易于使用的 sqlite 包装器.我建议你使用其中之一.
FMDB and BWDB are good and easy to use sqlite wrappers for objective c. I suggest you use one of those .
请注意,BWDB 在 lynda.com 教程中(这个),如果你在网上找不到它...留下评论,我会把它上传到某个地方.
Note that BWDB is in a lynda.com tutorial (this one) and if you don't find it on the web...leave a comment and i'll upload it somewhere.
你可以在你的应用程序中写东西的唯一地方是你的文档目录......所以......简单来说......如果数据库不在你的文档目录中......是只读的......也是..当你读/写你的数据库时..操作系统会复制文档目录中的数据库..并在那里进行所有的读写,这样你就可以在你的应用程序包中拥有一个数据库,但你不能编辑那个...所以你最终会得到 2 db.我自己也有同样的问题..我在更新应用程序时通过合并 2 db 来修复它
edit: the only place you can write stuff in your app is in your documents directory...so..it plain terms...if the db is not in your documents directory..is read-only..also..when you read/write to your db..the OS copies the db in the documents directory..and does all the reading and writing there so you can have a db in your app bundle but you can't edit that one...so you'll end up with 2 db.I had the same problem myself..and i fixed it by merging the 2 db when i updated the app
edit2:我上传了 BWDB 最终项目(你有你的包装器和项目,看看它是如何工作的)
edit2: i uploaded BWDB final project ( you have your wrapper there and project to see how it works)
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