Question

我从iphone开发开始，面临核心数据问题。

我有一个模型收集了几个实体，如员工，项目，项目类型等。在启动时，我创建了几个实体，我坚持通过核心数据框架。没问题。

当我想根据用户在UIToolbar内选择的标签显示项目列表时，问题就出现了。我已经设置了参数来显示每个启动的sql请求（-com.apple.CoreData.SQLDebug 1），真正尴尬的是，当我通过sqlite从核心数据访问我的数据库时，控制台中显示的查询给我结果，不，0行返回...

有人遇到过类似的问题吗？

以下是用于检索项目列表的代码：

NSArray* retVal = nil;
NSError *error = nil;

NSManagedObjectContext *moc = "context retrieved";
NSEntityDescription *entityDescription = [NSEntityDescription entityForName:@"Project" inManagedObjectContext:moc];
NSFetchRequest *request = [[[NSFetchRequest alloc] init] autorelease];
[request setEntity:entityDescription];
retVal = [moc executeFetchRequest:request error:&error];

NSLog(@"Project type: %@", [theProjType valueForKey:@"projectTypeName"]);
NSLog(@"Employee number: %@", [theEmployee valueForKey:@"employeeNumber"]);

NSPredicate *predicate = [NSPredicate predicateWithFormat: @"ANY myEmployees.employeeNumber = %d AND myProjectType.projectTypeName = %d", [theEmployee valueForKey:@"employeeNumber"], [theProjType valueForKey:@"projectTypeName"]];
[request setPredicate:predicate];
retVal = [moc executeFetchRequest:request error:&error];

此代码生成此sql请求（在sqlite db上启动时返回结果）：

SELECT DISTINCT 0, t0.Z_PK, t0.Z_OPT, t0.ZPROJECTNUMBER, t0.ZISEDITABLE, t0.ZPROJECTNAME, t0.ZISDELETABLE, t0.ZPROJECTEND, t0.ZPROJECTID, t0.ZPROJECTSTART, t0.ZCUSTOMERORDERNR, t0.ZMYCUSTOMER, t0.ZMYCOSTCENTRE, t0.ZMYPROJECTTYPE, t0.ZMYTRAVELTIMES FROM ZPROJECT t0 JOIN Z_4MYPROJECTS t1 ON t0.Z_PK = t1.Z_10MYPROJECTS1 JOIN ZEMPLOYEE t2 ON t1.Z_4MYEMPLOYEES = t2.Z_PK JOIN ZPROJECTTYPE t3 ON t0.ZMYPROJECTTYPE = t3.Z_PK WHERE ( t2.ZEMPLOYEENUMBER = ? AND  t3.ZPROJECTTYPENAME = ?)

Answer 1

NSPredicate *predicate = [NSPredicate predicateWithFormat: @"ANY myEmployees.employeeNumber = %d AND myProjectType.projectTypeName = %d", [theEmployee valueForKey:@"employeeNumber"], [theProjType valueForKey:@"projectTypeName"]];

你确定这是对的吗？ valueForKey：始终返回NSObject，但占位符为％d。这应该会产生奇怪的行为。试试％@而不是

核心数据问题

1 个答案: