通过Objective-C创建SQLite3数据库文件

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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。我希望字段名称被称为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，而是将其驻留/存储在手机上的某个位置。该表需要是可读/可写的。我已经对用户沙箱以及文档目录进行了一些阅读。我不确定我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。将文本字段的输入放入字符串后，将进行检查以查看我的tblStoreSQLite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.

概括：
1. Obj-C / SQLite创建名为tblStore的表的语法是什么，字段为strStoreNumber和 strStoreReg？
2. db文件应该驻留在哪里？我需要读取和写入tblStore db文件。
3.用户沙箱和文档目录之间有什么区别？

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"?

这就是我目前所拥有的：

This is what I have currently:

-(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，出现以下错误：

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，并且未能成功完成我尝试过的一些事情。非常感谢你们的帮助！

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!

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通过Objective-C创建SQLite3数据库文件

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