FMDB 用于从 iPhone 应用程序的数据库中读取数据
我正在使用以下代码从客户表中读取记录。由于某种原因，返回的结果集始终为空。
-(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;
}
我已多次检查数据库，它显示了数据，但由于某种原因 FMDB 无法检索它！
I am using the following code to read the records from the customers table. For some reason the resultset returned is always empty.
-(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;
}
I have checked in the database multiple times and it shows the data but for some reason the FMDB is not able to retrieve it!
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将数据库日志错误设置为 true，这将显示您登录控制台，您可以在其中找到问题。
set db log errors to true, this will show you log in console where you can find the problem.