Use of the ios CoreData framework, add, delete, modify, and query context data, association between tables, 1-to-many, 1-to-1, predicate query, multi-table join, ioscoredata

Use of the ios CoreData framework, add, delete, modify, and query context data, association between tables, 1-to-many, 1-to-1, predicate query, multi-table join, ioscoredata

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-(Void) viewDidLoad {

[SuperviewDidLoad];

[Self_creatTable]; // insert data

// [Self _ query]; // query data

// KVC is overbearing. It can be assigned a value even if readonly is passed through kvc. kvo is excellent.

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

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

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

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

}

# Pragma mark-_ query

-(Void) _ query {

// Initialize the Model

NSManagedObjectModel * model = [NSManagedObjectModelmergedModelFromBundles: nil];

// Create the basic library Coordinator

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

// Obtain the sandbox path

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

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

NSLog (@ "% @", path );

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

// Load the basic library path and basic library type for the Coordinator

[Psc addPersistentStoreWithType: NSSQLiteStoreTypeconfiguration: nilURL: url options: nilerror: nil];

// Create a context

NSManagedObjectContext * context = [[NSManagedObjectContextalloc] init];

Context. persistentStoreCoordinator = psc;

// Initialize the query request

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

// Predicate filtering (query condition)

# Pragma mark' ='

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

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

# 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 search

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

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

# Pragma mark 'between' fuzzy query

// Method 1

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

// Method 2

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

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

// Request. predicate = predict;

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

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

Request. sortDescriptors = @ [sort];

NSError * error;

// Execute the query statement

NSArray * array = [context executeFetchRequest: request error: & error]; // The returned result is an array.

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

// The number of query results. nsinteger is returned.

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

/*

//// Obtain using KVC

// For (NSManagedObject * student in array ){

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

//}

/// Obtain the KVC subclass

// For (Student * student in array ){

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

//}

* // KVC

// Obtain from the ing object

For (Teacher * teacherin array ){

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

}

}

# Pragma mark _ creatTable

-(Void) _ creatTable {

// Initialize the Model

NSManagedObjectModel * model = [NSManagedObjectModelmergedModelFromBundles: nil];

// Create the basic library Coordinator

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

// Obtain the sandbox path

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

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

NSLog (@ "% @", path );

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

// Load the basic library path and basic library type for the Coordinator

[Psc addPersistentStoreWithType: NSSQLiteStoreTypeconfiguration: nilURL: url options: nilerror: nil];

// Create a context

NSManagedObjectContext * context = [[NSManagedObjectContextalloc] 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 to create the NSManagedObject subclass class. The class is automatically created based on the entity (entity) table in the model (inherited from NSManagedObject and has attributes and methods of NSManagedObject) so you can directly create it 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 = [[NSFetchRequestalloc] initWithEntityName: @ "Teacher"];

// Predicate filtering (query condition)

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

// Request. predicate = predict;

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

For (Teacher * teacherin array ){

Student * student1 = [NSEntityDescriptioninsertNewObjectForEntityForName: @ "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 saved): delete data stored in the cache (database table not modified) before the delete statement is saved.

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

// Save

NSError * error;

[Contextsave: & error];

}

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