Question

这是我在Appdelegate.m中用来复制数据库的代码

- (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:@"LocalSongs.sqlite"];
        success = [fileManager copyItemAtPath:defaultDBPath toPath:dbPath error:&error];

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

}

这用于获取DBPath

- (NSString *) getDBPath {


    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory , NSUserDomainMask, YES);
    NSString *documentsDir = [paths objectAtIndex:0];

    return [documentsDir stringByAppendingPathComponent:@"LocalSongs.sqlite"];


}

这是我的播放列表插入方法

-(NSString *)InsertPlaylist :(NSString *)PlaylistName
{
    NSLog(@"passed");
    NSString *status;


    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory , NSUserDomainMask, YES);
    NSString *documentsDir = [paths objectAtIndex:0];
    NSString *dbPath=[[NSString alloc]initWithString:[documentsDir stringByAppendingPathComponent:@"LocalSongs.sqlite"]];

    NSLog(@"Database Path %@",dbPath);

    sqlite3_stmt    *statement;


    if (sqlite3_open([dbPath UTF8String], &database) == SQLITE_OK) {

        NSLog(@"open");

        NSString *insertSQL = [NSString stringWithFormat: @"INSERT INTO LOCALPLAYLIST (PLAYLISTNAME,getdate()) VALUES (\"%@\")",PlaylistName];

        const char *insert_stmt = [insertSQL UTF8String];
        sqlite3_prepare_v2(database, insert_stmt, -1, &statement, NULL);
        if (sqlite3_step(statement) == SQLITE_DONE)
        {
            status=@"Playlist Created";
        }

        else
        {
            status=@"Error occured";
        }


        return status;

    }
}

我遇到的问题是这个prepare_v2总是变得没有用。它总是执行else部分。

if (sqlite3_step(statement) == SQLITE_DONE)

这有什么问题？请帮帮我

Answer 1

我认为您的查询有误：您应该在您放置getdate()的位置添加列名，即代替

INSERT INTO LOCALPLAYLIST (PLAYLISTNAME,getdate()) VALUES (\"%@\")

你应该使用像

这样的东西

INSERT INTO LOCALPLAYLIST (PLAYLISTNAME,MYDATECOLUMN) VALUES (\"%@\",getdate())

sqlite3_prepare_v2后statement指针为NULL？

将sqlite3_prepare_v2和sqlite3_step的返回值与http://www.sqlite.org/c3ref/c_abort.html中的值进行比较，以便更好地了解出现问题的方法

如果（sqlite3_step（statement）== SQLITE_DONE）总是失败

1 个答案: