coredata数据库的使用方法，增删改查，条件查询，排序等,对于新手来说非常好的参考资料 不足之处，多多指教
//插入数据
+(BOOL)insertPersonname:(NSString*)name andage:(NSInteger)age andupdate:(NSDate*)update andsex:(NSString*)sex {
Person *Insertperson=[NSEntityDescription insertNewObjectForEntityForName:@"Person" inManagedObjectContext:kCoreDataContext];
Insertperson.name=name;
Insertperson.age=[NSNumber numberWithInteger:age];
Insertperson.updatedate=update;
Insertperson.sex=sex;
//保存, 将插入操作更新到数据库
NSError *error;
[kCoreDataContext save:&error];
if (error == nil) {
return YES;
}
return NO;
}
/**
- //条件查询
- @param Searchtype 1.为按更新时间 2.按年龄
- @param pageSize 2.查询个数
- @param age 3.年龄要求
- @param Sex 4.性别要求
- @param ascending 5.是否升序
- @return */
+(NSArray*)selectWithType:(NSInteger)Searchtype andpageSize:(NSInteger)pageSize andAge:(NSInteger)age andSex:(NSInteger)Sex andascending:(BOOL)ascending {
//创建查询请求对象
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Person"];
//根据参数进行升序降序排列
switch (Searchtype) {
case 1:
{
//按更新时间排列
NSSortDescriptor *sort=[NSSortDescriptor sortDescriptorWithKey:@"updatedate" ascending:ascending];
NSArray *sortDescriptors=[NSArray arrayWithObject:sort];
[request setSortDescriptors:sortDescriptors];
}
break;
case 2:
{
//按年龄排列
NSSortDescriptor *sort=[NSSortDescriptor sortDescriptorWithKey:@"age" ascending:ascending];
NSArray *sortDescriptors=[NSArray arrayWithObject:sort];
[request setSortDescriptors:sortDescriptors];
}
break;
default:
break;
}
if (pageSize!=0) {
[request setFetchLimit:pageSize];//设定查询个数
}
// [request setFetchOffset:0];//从第几个开始查询
NSString *sexStr;
if (Sex==1) {
sexStr=@"男";
}else{
sexStr=@"女";
}
//根据年龄和性别
if (age==1) {
request.predicate=[NSPredicate predicateWithFormat:@"sex=%@",sexStr];
}else{
request.predicate=[NSPredicate predicateWithFormat:@"sex=%@ AND age<=%d",sexStr,20];
}
NSError *error;
NSArray *arr = [kCoreDataContext executeFetchRequest:request error:&error];
if (error == nil) {
return arr;
}
return nil;
}
//查询所有人 +(NSArray *)searchPerson {
//创建查询请求对象
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Person"];
NSError *error;
NSArray *arr = [kCoreDataContext executeFetchRequest:request error:&error];
if (error == nil) {
return arr;
}
return nil;
}
//更新数据 +(void)updatePeson:(Person*)peson andkey:(NSString*)key anddata:(NSString*)data { //先查出数据, 然后再更新 NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Person"];
//添加查询条件
request.predicate=[NSPredicate predicateWithFormat:@"name=%@",peson.name];
//执行查询
NSArray *arr = [kCoreDataContext executeFetchRequest:request error:nil];
if ([key isEqualToString:@"name"]) {
for (Person *p in arr) {
p.name = data;
}
}else if ([key isEqualToString:@"age"])
{
for (Person *p in arr) {
p.age=@([data integerValue]);
}
}else{
for (Person *p in arr) {
p.sex=data;
}
}
[kCoreDataContext save:nil];
}
//删除某一个数据
-
(void)deleteWithPerson:(Person *)person { //删除数据 [kCoreDataContext deleteObject:person];
//保存, 将删除操作更新到数据库中 [kCoreDataContext save:nil];
}
//删除所有数据
+(void)deleteAllDatas {
NSFetchRequest *request = [NSFetchRequest fetchRequestWithEntityName:@"Person"];
NSArray *arr = [kCoreDataContext executeFetchRequest:request error:nil];
for (Person*p in arr) {
//删除数据
[kCoreDataContext deleteObject:p];
}
//保存, 将删除操作更新到数据库中
[kCoreDataContext save:nil];
}