objective-c - 从 iPhone 应用程序的数据库中读取 FMDB

Question

我正在使用以下代码从客户表中读取记录。由于某种原因，返回的结果集总是空的。

    -(NSMutableArray *) getCustomers
{
    NSMutableArray *customers = [[NSMutableArray alloc] init];

    NSString *databaseName = @"Customers.db";

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

    NSString *databasePath = [documentsDir stringByAppendingPathComponent:databaseName];

    FMDatabase *db = [FMDatabase databaseWithPath:databasePath];

    if(![db open]) 
    {
        return nil; 
    }

    FMResultSet *results = [db executeQuery:@"SELECT * FROM customers"];

    while([results next]) 
    {
        Customer *customer = [[Customer alloc] init];


        customer.firstName = [results stringForColumn:@"firstname"];
        customer.lastName = [results stringForColumn:@"lastname"];

        [customers addObject:customer];

    }

    [db close];

    return customers; 


}

我多次检查数据库，它显示了数据，但出于某种原因，FMDB 无法检索它!

Answer 1

将 db log errors 设置为 true，这将显示您登录到可以找到问题的控制台。

FMDatabase *db = [FMDatabase databaseWithPath:databasePath];
db.logsErrors = YES;