Creation of the CoreData database

CoreData database Add, delete, change, check (show in TableView)

First, create a new Datamodel database table (Import CoreData Class)

Create a new nsmanagedobject, generate the Estudent class

2. #import <Foundation/Foundation.h>

4. #import <CoreData/CoreData.h>

8. @class NSManagedObject;

12. @interface EStudent : NSManagedObject

16. @property (nonatomic, retain) NSNumber * age;

18. @property (nonatomic, retain) NSNumber * height;

20. @property (nonatomic, retain) NSString * name;

22. @property (nonatomic, retain) NSManagedObject *school;

26. @end

28. #import "EStudent.h"

30. //#import "NSManagedObject.h"

32. #import <CoreData/CoreData.h>

34. @implementation EStudent

38. @dynamic age;

40. @dynamic height;

42. @dynamic name;

44. @dynamic school;

48. @end

Second, custom xib, set up and delete the search view

Note the delegate settings for TableView

Third, create the database

-(void) Preparecoredata

{

A. Creating a database-creating a model file

B. Creating a table-creating an entity

C. Building the entity class Model

D. Writing a code initialization framework

1. Create the Nsmanagedobjectmodel model class based on the model file

Nsurl * FileURL = [[NSBundle mainbundle] urlforresource:@ "Main" withextension:@ "MOMD"];

Nsmanagedobjectmodel * Managedobjectmodel = [[Nsmanagedobjectmodelalloc] initwithcontentsofurl:fileurl];

2. Associating model classes and database files

2.1 Creating a Persistence Coordinator

Nspersistentstorecoordinator * coordinator = [[Nspersistentstorecoordinator Alloc]initwithmanagedobjectmodel: Managedobjectmodel];

2.2 Specifying a persistence class for the Coordinator

NSString * DbPath = [Nshomedirectory () stringbyappendingpathcomponent:@ "Documents/main.sqlite"];

NSLog (@ "Path:%@", DbPath);

Nserror * error = NIL;

[Coordinator AddPersistentStoreWithType:NSSQLiteStoreTypeconfiguration:nil Url:[nsurl Fileurlwithpath:dbpath] options:nilerror:&error];

if (Error) {

NSLog (@ "%@", error);

}

3. Create Nsmanagedobjectcontext context

Self.context = [[Nsmanagedobjectcontext alloc] init];

Self.context.persistentStoreCoordinator = coordinator;

}

-(void) Initialdatasource

{

Self.datasource = [Nsmutablearray new];

Reading data

1. Create nsfetchrequest, fetch data request class

Nsfetchrequest * request = [[Nsfetchrequest alloc]initwithentityname:@ "Estudent"];

Nserror * error = NIL;

2. Fetching data from the current context

Nsarray * array = [Self.context executefetchrequest:requesterror:&error];

if (Error) {

NSLog (@ "%@", error);

Return

}

[Self.datasource Addobjectsfromarray:array];

}

Iv. Customizing the content of Tableviewcell

#pragma mark-tableview Delegate

-(Nsinteger) TableView: (UITableView *) TableView numberofrowsinsection: (nsinteger) Section

{

return self.dataSource.count;

}

-(UITableViewCell *) TableView: (UITableView *) TableView Cellforrowatindexpath: (Nsindexpath *) indexpath{

Mytableviewcell * cell = [tableviewdequeuereusablecellwithidentifier:@ "cell"];

if (!cell) {

cell = [[UITableViewCell alloc] initwithstyle:uitableviewcellstylesubtitle reuseidentifier:@ "Cell"];

cell = [[[NSBundle Mainbundle] loadnibnamed:@ "Mytableviewcell" owner:self Options:nil]firstobject];

}

Estudent * s = [Self.datasource objectAtIndex:indexPath.row];

Cell.textLabel.text = S.name;

Cell.detailTextLabel.text = [NSString stringwithformat:@ "%@", S.age];

Cell.nameTF.text = S.name;

Cell.heightTF.text = [NSString stringwithformat:@ "%@", s.height];

Cell.ageTF.text = [NSString stringwithformat:@ "%@", S.age];

return cell;

}

-(CGFloat) TableView: (UITableView *) TableView Heightforrowatindexpath: (Nsindexpath *) Indexpath

{

return 90;

}

V. Increase and revise the operation of the check

??? Increase

Insert operation

1. Create an entity class from the Nsentitydescription class

Arg1. Entity name (table name, name of entity Class); arg2. Context

Estudent * s = [nsentitydescriptioninsertnewobjectforentityforname:@ "Estudent" InManagedObjectContext:self.context] ;

S.name = Self.nameTF.text;

S.age = [NSNumber numberWithInt:self.ageTF.text.intValue];

S.height = [NSNumbernumberWithFloat:self.heightTF.text.floatValue];

2. Deposit into the database

Nserror * error = NIL;

[Self.context save:&error];

[Self.datasource addobject:s];

[Self.tableview Reloaddata];

??? By deleting

Nsindexpath * Path = [Self.tableview Indexpathforselectedrow];

Delete

1. Find the object you want to delete

Estudent * student = [Self.datasource objectAtIndex:path.row];

2. Deleting an object from the context

[Self.context deleteobject:student];

3. Save context to File

[Self.context Save:nil];

[Self.datasource removeobject:student];

[Self.tableview Reloaddata];

??? Change

Change data

1. Find the object you want to modify

Nsindexpath * Path = [Self.tableview Indexpathforselectedrow];

Estudent * student = [Self.datasource objectAtIndex:path.row];

2. Modifications

Student.name = Self.nameTF.text;

3. Save

[Self.context Save:nil];

[Self.tableview Reloaddata];

??? Check

Inquire

1. Create a Query Request class

Nsfetchrequest * request = [[Nsfetchrequest alloc]initwithentityname:@ "Estudent"];

2. Set Filter Criteria

// =

CONTAINS

Beginswith

Endswithd

nspredicate * predicate = [nspredicate predicatewithformat:@ "name CONTAINS%@", Self.nameTF.text];

Request.predicate = predicate;

N.

Nserror * error = NIL;

Nsarray * array = [Self.context executefetchrequest:requesterror:&error];

if (Error) {

NSLog (@ "%@", error);

}

[Self.datasource removeallobjects];

[Self.datasource Addobjectsfromarray:array];

[Self.tableview Reloaddata];

Creation of the CoreData database