我试图在运行时通过 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，我还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位置。该表需要可读/可写。我已经阅读了一些关于“用户沙箱”和“文档目录”的文章。我不确定我是否理解两者之间的区别。理想情况下，我的应用程序会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，将检查我的“tblStore”SQLite 表是否存在，如果不存在，将创建该表。

回顾一下: 1. Obj-C/SQLite 创建一个名为“tblStore”且字段为“strStoreNumber”和“strStoreReg”的表的语法是什么？ 2. db 文件应该放在哪里？我需要读取和写入 tblStore 数据库文件。 3.“用户沙箱”和“文档目录”有什么区别？

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，出现以下错误:

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这些东西的人，因为我是新手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!

最佳答案

//创建数据库

-(NSString *) filePath
{
 NSArray *paths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
 NSString *documentDirectory=[paths objectAtIndex:0];
 return [documentDirectory stringByAppendingPathComponent:@"LoginDatabase.sql"];
}

//打开数据库

-(void)openDB
{
 if(sqlite3_open([[self filePath]UTF8String], &db) !=SQLITE_OK)
 {
   sqlite3_close(db);
   NSAssert(0, @"Database failed to Open");
 }
}

//创建表

-(void) createTableNamed:(NSString*)tableName withField1:(NSString*) field1 withField2:(NSString*) field2

{
   char *err;
   NSString *sql=[NSString stringWithFormat:@" CREATE TABLE IF NOT EXISTS '%@'('%@' TEXT PRIMARY KEY,'%@' TEXT);",tableName,field1,field2];

   if(sqlite3_exec(db, [sql UTF8String], NULL, NULL, &err) !=SQLITE_OK)
   {
    sqlite3_close(db);
    NSAssert(0, @"Table failed to create");
   }
}

//插入记录

-(void)insertrecordIntoTable:(NSString*) tableName withField1:(NSString*) field1 field1Value:(NSString*)field1Vaue andField2:(NSString*)field2 field2Value:(NSString*)field2Value
{

  NSString *sqlStr=[NSString stringWithFormat:@"INSERT INTO '%@'('%@','%@')VALUES(?,?)",tableName,field1,field2];
 const char *sql=[sqlStr UTF8String];

 sqlite3_stmt *statement1;

 if(sqlite3_prepare_v2(db, sql, -1, &statement1, nil)==SQLITE_OK)
 {
  sqlite3_bind_text(statement1, 1, [field1Vaue UTF8String], -1, nil);
  sqlite3_bind_text(statement1, 2, [field2Value UTF8String], -1, nil);
 }
 if(sqlite3_step(statement1) !=SQLITE_DONE)
    NSAssert(0, @"Error upadating table");
 sqlite3_finalize(statement1);
}

//从表中获取数据

-(void)getAllRowsFromTableNamed:(NSString *)tableName
{
  NSString *field1Str,*field2Str;

  NSString *qsql=[NSString stringWithFormat:@"SELECT * FROM %@",tableName];
  sqlite3_stmt *statement;
  if(sqlite3_prepare_v2(db, [qsql UTF8String], -1, &statement, nil)==SQLITE_OK)
  {
   while(sqlite3_step(statement) ==SQLITE_ROW)
   {
     char *field1=(char *) sqlite3_column_text(statement, 0);
     char *field2=(char *) sqlite3_column_text(statement, 1);

     field1Str=[[NSString alloc]initWithUTF8String:field1];
     field2Str=[[NSString alloc] initWithUTF8String:field2];

     NSString *str=[NSString stringWithFormat:@"%@ - %@",field1Str,field2Str];
     NSLog(@"%@",str);
   }
}

在viewDidLoad中调用方法

- (void)viewDidLoad
{

  [self openDB];
  [self createTableNamed:@"Login" withField1:@"USERNAME" withField2:@"PASSWORD"];
  [self insertrecordIntoTable:@"Login" withField1:@"USERNAME" field1Value:username andField2:@"PASSWORD" field2Value:password];

}

其中用户名和密码是 NSString 值；

关于iphone - 通过 Objective-C 创建 SQLite3 数据库文件，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/10540728/