IosCoreData framework is used to add, delete, modify, and query context data, association between tables, 1-to-many, 1-to-1, predicate query, and multi-Table connection.

IosCoreData framework is used to add, delete, modify, and query context data, association between tables, 1-to-many, 1-to-1, predicate query, and multi-Table connection.

-(void) viewDidLoad {

[super viewDidLoad];



[self _creatTable]; // Insert data



// [self _query]; // query data





// KVC is very domineering, even though readonly can be assigned via kvc, the essence of kvo

// Book * book = [[Book alloc] init];

//// book.name = @ "book1";

// [book setValue: @ "book2" forKey: @ "name"];

// NSLog (@ "% @", book.name);

}



#pragma mark-_query query

-(void) _query {

// Initialize the model

NSManagedObjectModel * model = [NSManagedObjectModel mergedModelFromBundles: nil];



// Create a basic library coordinator

NSPersistentStoreCoordinator * psc = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: model];



// Get the sandbox path

NSString * path = [NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES) firstObject];

path = [path stringByAppendingPathComponent: @ "coreData.sqlite"];

NSLog (@ "% @", path);

NSURL * url = [[NSURL alloc] initFileURLWithPath: path];



// Load the base library path and base library type for the coordinator

[psc addPersistentStoreWithType: NSSQLiteStoreType configuration: nil URL: url options: nil error: nil];

// create context

NSManagedObjectContext * context = [[NSManagedObjectContext alloc] init];

context.persistentStoreCoordinator = psc;





// Initialize the query request

NSFetchRequest * request = [[NSFetchRequest alloc] initWithEntityName: @ "Teacher"];



// Predicate filtering (query condition)

#pragma mark '='

// NSPredicate * predict = [NSPredicate predicateWithFormat: @ "name =% @", @ "zhangks"];

// NSPredicate * predict = [NSPredicate predicateWithFormat: @ "name = 'zhangks'"];

#pragma mark '>'

// NSPredicate * predict = [NSPredicate predicateWithFormat: @ "age> 10"];

// NSPredicate * predict = [NSPredicate predicateWithFormat: @ "name in% @", @ [@ "zhangsk", @ "jack"]];

#pragma mark 'like' fuzzy query

// NSPredicate * predict = [NSPredicate predicateWithFormat: @ "name like% @", @ "zha *"];

// NSPredicate * predict = [NSPredicate predicateWithFormat: @ "name like% @", @ "* zha *"];

// NSPredicate * predict = [NSPredicate predicateWithFormat: @ "name like% @", @ "* zha"];







#pragma mark 'and' and '&&' fuzzy query

// NSPredicate * predict = [NSPredicate predicateWithFormat: @ "name =% @ and age = 19", @ "zhangks"];

// NSPredicate * predict = [NSPredicate predicateWithFormat: @ "name =% @ && age = 19", @ "zhangks"];



#pragma mark 'between' fuzzy query

// Way 1

// NSPredicate * predict = [NSPredicate predicateWithFormat: @ "age between {20,30}"];



// Way 2

// NSPredicate * predict = [NSPredicate predicateWithFormat: @ "age between% @", @ [@ "10", @ "29"]];

// predict = [NSPredicate predicateWithFormat: predict.predicateFormat];



// request.predicate = predict;



// Data sorting ascending = YES order, ascending = NO reverse order

NSSortDescriptor * sort = [NSSortDescriptor sortDescriptorWithKey: @ "name" ascending: YES];

request.sortDescriptors = @ [sort];



NSError * error;

// execute query

NSArray * array = [context executeFetchRequest: request error: & error]; // The query result returns an array

// NSInteger count = [context countForFetchRequest: request error: & error];

// Number of query results, return nsinteger





// NSLog (@ "% li", count);



/ *

// // Obtained in KVC

// for (NSManagedObject * student in array) {

// NSLog (@ "————————————————————% @,% li", [student valueForKey: @ "name"], [[student / Users / zhangxin /Desktop/OC/UI/5.19/5.21coreData/testtestcoredata/testtestcoredata/ViewController.m valueForKey: @ "age"] integerValue]);

//}



// // Obtained by subclass KVC

// for (Student * student in array) {

// NSLog (@ "% li,% @", [student.age integerValue], [student valueForKey: @ "name"]);

//}

* /// KVC



// Obtained through the mapping object

for (Teacher * teacher in array) {

NSLog (@ "% @", teacher.name);

}





}



#pragma mark _creatTable

-(void) _creatTable {

// Initialize the model

NSManagedObjectModel * model = [NSManagedObjectModel mergedModelFromBundles: nil];



// Create a basic library coordinator

NSPersistentStoreCoordinator * psc = [[NSPersistentStoreCoordinator alloc] initWithManagedObjectModel: model];



// Get the sandbox path

NSString * path = [NSSearchPathForDirectoriesInDomains (NSDocumentDirectory, NSUserDomainMask, YES) firstObject];

path = [path stringByAppendingPathComponent: @ "coreData.sqlite"];

NSLog (@ "% @", path);

NSURL * url = [[NSURL alloc] initFileURLWithPath: path];



// Load the base library path and base library type for the coordinator

[psc addPersistentStoreWithType: NSSQLiteStoreType configuration: nil URL: url options: nil error: nil];

// create context

NSManagedObjectContext * context = [[NSManagedObjectContext alloc] init];

context.persistentStoreCoordinator = psc;





// // Insert data

// NSManagedObject * student = [NSEntityDescription insertNewObjectForEntityForName: @ "Student" inManagedObjectContext: context];

// [student setValue: @ "zhangks" forKey: @ "name"];

// [student setValue: @ (19) forKey: @ "age"];

//

// NSManagedObject * teacher = [NSEntityDescription insertNewObjectForEntityForName: @ "Teacher" inManagedObjectContext: context];

// [teacher setValue: @ "zhqo" forKey: @ "name"];



// Insert data New NSManagedObject subclass class, automatically create a class based on the entity table in the model (inherited from NSManagedObject, with the properties and methods of NSManagedObject), so you can create it directly with the class name

// Student * student = [NSEntityDescription insertNewObjectForEntityForName: @ "Student" inManagedObjectContext: context];

// student.name = @ "jack";

// student.age = @ (29);

//

//

//

// Teacher * teacher = [NSEntityDescription insertNewObjectForEntityForName: @ "Teacher" inManagedObjectContext: context];

// teacher.name = @ "limei";



// Initialize the query request

NSFetchRequest * request = [[NSFetchRequest alloc] initWithEntityName: @ "Teacher"];



// Predicate filtering (query condition)

// NSPredicate * predict = [NSPredicate predicateWithFormat: @ "name = 'limei'"];



// request.predicate = predict;



NSArray * array = [context executeFetchRequest: request error: nil];

for (Teacher * teacher in array) {

Student * student1 = [NSEntityDescription insertNewObjectForEntityForName: @ "Student" inManagedObjectContext: context];

student1.name = @ "jim";

student1.age = @ (12);

student1.relationship = teacher;













NSLog (@ "% @,% @", teacher.name, student1.relationship.name);

//// teacher.name = @ "liuwu";

//// [context deleteObject: teacher];

//

}



// NSSet * deleteSet = [context deletedObjects]; // Delete (not save), delete data stored in the cache (library table is not modified) before the delete statement is executed and not saved

// NSSet * insertSet = [context insertedObjects]; // Same as above



// save

NSError * error;

[context save: & error];

}

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