Question

我正在尝试从sqlite数据库中提取数据。我添加了“libsqlite3.0.dylib”文件并将创建的sqlite DB复制到我的app文件夹中。我在appdelegate文件中创建了两个方法。他们是

//To copy DB
- (void) copyDatabaseIfNeeded {

    //Using NSFileManager we can perform many file system operations.
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSError *error;
    NSString *dbPath = [self getDBPath];
    BOOL success = [fileManager fileExistsAtPath:dbPath];

    if(!success) {
        NSLog(@"DB File %@ does not exists", dbPath);
        NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"tms.sqlite"];
        success = [fileManager copyItemAtPath:defaultDBPath toPath:dbPath error:&error];

        NSLog(@"Successfully copied db file to path %@", dbPath);
        if (!success)
            NSLog(@"Failed to create writable database file with message '%@'.", [error localizedDescription]);
    } else {
        NSLog(@"DB File %@ already exists", dbPath);
    }
}

//To get DB path
-(NSString *)getDBPath{
    NSArray *paths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentDir=[paths objectAtIndex:0];
    return [documentDir stringByAppendingPathComponent:@"sampleDB.sqlite"];
}

我在didFinishLaunchingWithOptions中调用了copyDatabaseIfNeeded（），我在ViewController.m文件中添加了一个方法。那是

-(void)Display
{
    SqlitAppDelegate *appDelegate=(SqlitAppDelegate *)[UIApplication sharedApplication].delegate;
    NSString *dbPath=[appDelegate getDBPath];
    if (sqlite3_open([dbPath UTF8String], &myDB) == SQLITE_OK)
    {
        NSLog(@"Database opned successflly");
        const char *sql = "select * from sampleTable";
        NSLog(@"%s",sql);
        sqlite3_stmt *selectstmt;
        if(sqlite3_prepare_v2(myDB, sql, -1, &selectstmt, NULL) == SQLITE_OK)
            NSLog(@"Prepared successfully");
        else
        {
            NSLog(@"Preparation failed");
            NSLog(@"%s",sqlite3_errmsg(myDB));
            NSLog(@"%d",sqlite3_errcode(myDB));
        }


    }
    else
        NSLog(@"Couldn't open database");


}

我在didViewLoad方法中调用了这个方法。

我得到了以下输出：

2013-03-20 12：02：24.026 SqliteSample2 [951：11303]数据库成功启用
2013-03-20 12：02：24.027 SqliteSample2 [951：11303] select * from sampleTable
2013-03-20 12：02：24.028 SqliteSample2 [951：11303]准备失败
2013-03-20 12：02：24.029 SqliteSample2 [951：11303]没有这样的表：sampleTable
2013-03-20 12：02：24.029 SqliteSample2 [951：11303] 1

有人告诉我做什么??????

提前致谢...........

Answer 1

在视图控制器中导入SqlitAppDelegate，并在@implementation ViewController

之后创建SqlitAppDelegate *app之类的对象

在 viewDidLoad 中写

    app= (SqlitAppDelegate *)[[UIApplication sharedApplication]delegate];

    databasepath = [app getDBPath];

    if(sqlite3_open([databasepath UTF8String], &dbAssessor) == SQLITE_OK) 
    {
        NSString *sql = [NSString stringWithFormat:@"select * from SampleTable ;"];

        sqlite3_stmt *selectstmt;
        const char *sel_query=[sql UTF8String];

        if(sqlite3_prepare(dbAssessor, sel_query, -1, &selectstmt, NULL) == SQLITE_OK)
        {
            while(sqlite3_step(selectstmt) == SQLITE_ROW)
            {   
                NSLog(@"Prepared Successfully...");
            }
        }
        sqlite3_finalize(selectstmt);
    }
    else
        sqlite3_close(dbAssessor);

请尝试此代码并将结果传递给我。享受!!!

在Sqlite iOS中找不到表格

1 个答案: