Question

在我的应用程序中，我在sqlite数据库上进行读取，写入和删除（以db格式），它在模拟器中工作正常，但在实际设备中无效（给出错误：No such table found）。我非常努力寻找解决方案，但找不到或可能是我误解的东西。

我的数据库在

中

/ users / My Name / library / developer / Core 模拟器/设备/器件N-ID /数据/应用/ APP-ID /文档/我的数据库中。

- (NSString *) getWritableDBPath {

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory , NSUserDomainMask, YES);
NSString *documentsDir = [paths objectAtIndex:0];
return [documentsDir stringByAppendingPathComponent:mydaatabase];

}

我很困惑在实际的iOS设备上运行时我需要复制数据库的地方和核心问题。对此有任何帮助将非常有帮助

-(void)createEditableCopyOfDatabaseIfNeeded
{

BOOL success;
NSFileManager *fileManager1 = [NSFileManager defaultManager];
NSError *error;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
                                                     NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:mydaatabase];
NSLog(@"=======%@", writableDBPath);

success = [fileManager1 fileExistsAtPath:writableDBPath];
if (success)
    return;

NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath]
                          stringByAppendingPathComponent:mydaatabase];
NSLog(@"=======%@", [NSBundle mainBundle]);

success = [fileManager1 copyItemAtPath:defaultDBPath
                               toPath:writableDBPath
                                error:&error];


if(!success)
{
    NSAssert1(0,@"Failed to create writable database file with Message : '%@'.", 
    [error localizedDescription]);
}
}

Answer 1

以下是使用SQLite数据库的步骤。

在SQLite中创建数据库，添加具有良好结构的必需表。并将其添加到您的应用程序中。
现在，转到您的应用，从左侧面板，中间面板中选择项目 - ＆gt;一般 - ＆gt;链接的框架和库（最后一个）添加libsqlite3.0.tbd（这取决于您的Xcode版本。）

现在，在your-object.h

中定义以下方法

#import <sqlite3.h>

+ (NSString *)getDBPath;
+ (void)copyDatabaseIfNeeded;
+ (void)openDatase;

在your-object.m

中实施这些内容

static sqlite3 *database;

#pragma mark - Copy and open databse

+ (NSString *)getDBPath
{
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory , NSUserDomainMask, YES);
    NSString *documentsDir = [paths objectAtIndex:0];
    return [documentsDir stirngByAppendingPathComponent:@"dbName.sqlite"];
}

+ (void)copyDatabaseIfNeeded
{
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSError *error;

    NSString *dbPath = [self getDBPath];
    BOOL success = [fileManager fileExistsAtPath:dbPath];

    if(!success)
    {
        NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"dbName.sqlite"];
        success = [fileManager copyItemAtPath:defaultDBPath toPath:dbPath error:&error];

        if (!success)
            NSAssert1(0, @"Failed to create writable database file with message '%@'.", [error localizedDescription]);
    }
}

+ (void)openDatase
{
    NSString *dbPath = [self getDBPath];

    if (sqlite3_open([dbPath UTF8String], &database) == SQLITE_OK)
    {
        NSLog(@"Database Successfully Opened.");
    }
    else
    {
        NSLog(@"Error in opening database.");
    }
}

然后在AppDelegate.m
中调用application: didFinishLaunchingWithOptions:中的方法
```
[DataManager copyDatabaseIfNeeded];
```
每当您想要使用数据库执行任务时，请打开它并检查。

用于插入数据库

     + (void)insertData
     {
         const char *dbpath = [[self getDBPath] UTF8String];

         if (sqlite3_open(dbpath, &database) == SQLITE_OK)
         {
             NSString *strSQL = [NSString stringWithFormat:@"INSERT INTO table name………………."];
             const char *insertQuery = [strSQL UTF8String];
             sqlite3_stmt *insert_stmt;

             if (sqlite3_prepare_v2(database, insertQuery, -1, &insert_stmt, NULL) == SQLITE_OK)
             {
                 if (sqlite3_step(insert_stmt) == SQLITE_DONE)
                 {
                    // Code
                 }
                 else
                 {
                     NSLog(@"error");
                 }
             }
             sqlite3_finalize(insert_stmt);
             sqlite3_close(database);
        }
    }

7。完成....享受数据库。

Answer 2

检查您的.sqlite文件是否已添加到项目Copy Bundle Resources中的Build Phases。如果不存在，请将其添加到项目中。

此外，我无法找到打开数据库的代码。因此，在ViewController.h文件中，声明Sqlite *database;

在ViewController.m文件中，

-(void)databaseOpen

{
    NSArray *paths=NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory=[paths objectAtIndex:0];
    NSString *myDBnew=[documentsDirectory stringByAppendingPathComponent:@"yourSqliteFile.sqlite"];

    database =[[Sqlite alloc]init];
    [database open:myDBnew];
    NSLog(@"path: %@", myDBnew);

    NSLog(@"Database opened");

}

并在[self databaseOpen];的任意位置调用它，然后编写查询。

另外，-(void)createEditableCopyOfDatabaseIfNeeded中的AppDelegate.m看起来应该是这样的：

- (void)createEditableCopyOfDatabaseIfNeeded
{
    // First, test for existence.
    BOOL success;
    NSFileManager *fileManager = [NSFileManager defaultManager];
    NSError *error;
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:@"yourSqliteFile.sqlite"];
    success = [fileManager fileExistsAtPath:writableDBPath];
    if (success) return;

    // The writable database does not exist, so copy the default to the appropriate location.

    NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"yourSqliteFile.sqlite"];
    success = [fileManager copyItemAtPath:defaultDBPath toPath:writableDBPath error:&error];
    if (!success) {
        NSAssert1(0, @"Failed to create writable database file with message '%@'.", [error localizedDescription]);
    }


}

在-(void)createEditableCopyOfDatabaseIfNeeded

中致电didFinishLaunchingWithOptions:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.

    [self createEditableCopyOfDatabaseIfNeeded];
    return YES;
}

这应该让你去。

我在db格式的sqlite数据库不能在实际设备上工作，但在模拟器

2 个答案: