Question

我不熟悉在目标C中进行开发，并且正在努力进入IF语句（sqlite3_exec == SQLITE_OK）。我一直在使用教程，似乎无法找到我的答案。

有人能告诉我哪里出错吗？

-(IBAction)addItemButton:(id)sender {
    char *error;

    if (sqlite3_open([dbPathString UTF8String], &itemDB) == SQLITE_OK) {
        NSString *insertStat = [NSString stringWithFormat:@"INSERT INTO ITEMS(ITEM) values ('%s')", [self.itemField.text UTF8String]];

        const char *insert_stat = [insertStat UTF8String];


        if (sqlite3_exec(itemDB, insert_stat, NULL, NULL, &error)== SQLITE_OK) {
            NSLog(@"Item Added");

            Item *item = [[Item alloc]init];

            [item setItem:self.itemField.text];

            [arrayOfItem addObject:item];
        }else{
            NSLog(@"Item not added");
        }

        sqlite3_close(itemDB);
    }
}

Answer 1

我编写了一个简单的SQLite帮助程序，用于执行一般数据库任务，只需几行代码，例如从数据库中获取记录，插入，更新和删除记录。 Source code can be found here with example

下载并拖动，在项目中删除ZeeSQLiteHelper类，并在ZeeSQLiteHelper类中设置数据库名称。

获取记录示例：

[ZeeSQLiteHelper initializeSQLiteDB];
NSString *query = @"SELECT * FROM recipes";
NSMutableArray *results = [ZeeSQLiteHelper readQueryFromDB:query];
[ZeeSQLiteHelper closeDatabase];

插入

[ZeeSQLiteHelper initializeSQLiteDB];
NSString *queryString = [NSString stringWithFormat:@"insert into %@ (%@,%@) VALUES ('%@','%@')",downloadsTblName, tblAttrFileName, tblAttrFileURL, downloadInfo.fileName, downloadInfo.fileURL];
[ZeeSQLiteHelper executeQuery:queryString];
[ZeeSQLiteHelper closeDatabase];

有关更新

[ZeeSQLiteHelper initializeSQLiteDB];
NSString *queryString = [NSString stringWithFormat:@"UPDATE %@ SET %@='%@' WHERE %@='%@'",downloadsTblName, tblAttrFileName, newFilePath.lastPathComponent, tblAttrFileName,oldFilePath.lastPathComponent];
[ZeeSQLiteHelper executeQuery:queryString];
[ZeeSQLiteHelper closeDatabase];

删除

[ZeeSQLiteHelper initializeSQLiteDB];
NSString *queryString = [NSString stringWithFormat:@"DELETE FROM %@ WHERE %@='%@'",downloadsTblName, tblAttrFileName,downloadedFileObj.videoTitle];
[ZeeSQLiteHelper executeQuery:queryString];
[ZeeSQLiteHelper closeDatabase];

将在控制台上记录适当的成功或失败消息。

sqlite3_exec == SQLITE_OK失败

1 个答案: