來源：http://www.yifeiyang.net/iphone-developer-advanced-9-management-database-using-sqlite/
代碼整體構造如下：
首先創建如下格式的數據庫文件：
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$ sqlite3 sample.dbsqlite> CREATE TABLE TbNote( ...> id INTEGER PRIMARY KEY, ...> title VARCHAR(255), ...> body VARCHAR(255) ...> ); |
創建DTO（Data Transfer Object）
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//TbNote.h#import <Foundation/Foundation.h>@interface TbNote : NSObject { int index; NSString *title; NSString *body;}@property (nonatomic, retain) NSString *title;@property (nonatomic, retain) NSString *body;- (id)initWithIndex:(int)newIndex Title:(NSString *)newTitle Body:(NSString *)newBody;- (int)getIndex;@end//TbNote.m#import "TbNote.h"@implementation TbNote@synthesize title, body;- (id)initWithIndex:(int)newIndex Title:(NSString *)newTitle Body:(NSString *)newBody{ if(self = [super init]){ index = newIndex; self.title = newTitle; self.body = newBody; } return self;}- (int)getIndex{ return index;}- (void)dealloc { [title release]; [body release]; [super dealloc];}@end |
創建DAO（Data Access Objects）
這裏將 FMDB 的函數調用封裝爲 DAO 的方式。
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//BaseDao.h#import <Foundation/Foundation.h>@class FMDatabase;@interface BaseDao : NSObject { FMDatabase *db;}@property (nonatomic, retain) FMDatabase *db;-(NSString *)setTable:(NSString *)sql;@end//BaseDao.m#import "SqlSampleAppDelegate.h"#import "FMDatabase.h"#import "FMDatabaseAdditions.h"#import "BaseDao.h"@implementation BaseDao@synthesize db;- (id)init{ if(self = [super init]){ // 由 AppDelegate 取得打開的數據庫 SqlSampleAppDelegate *appDelegate = (SqlSampleAppDelegate *)[[UIApplication sharedApplication] delegate]; db = [[appDelegate db] retain]; } return self;}// 子類中實現-(NSString *)setTable:(NSString *)sql{ return NULL;}- (void)dealloc { [db release]; [super dealloc];}@end |
下面是訪問 TbNote 表格的類。
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//TbNoteDao.h#import <Foundation/Foundation.h>#import "BaseDao.h"@interface TbNoteDao : BaseDao {}-(NSMutableArray *)select;-(void)insertWithTitle:(NSString *)title Body:(NSString *)body;-(BOOL)updateAt:(int)index Title:(NSString *)title Body:(NSString *)body;-(BOOL)deleteAt:(int)index;@end//TbNoteDao.m#import "FMDatabase.h"#import "FMDatabaseAdditions.h"#import "TbNoteDao.h"#import "TbNote.h"@implementation TbNoteDao-(NSString *)setTable:(NSString *)sql{ return [NSString stringWithFormat:sql, @"TbNote"];}// SELECT-(NSMutableArray *)select{ NSMutableArray *result = [[[NSMutableArray alloc] initWithCapacity:0] autorelease]; FMResultSet *rs = [db executeQuery:[self setTable:@"SELECT * FROM %@"]]; while ([rs next]) { TbNote *tr = [[TbNote alloc] initWithIndex:[rs intForColumn:@"id"] Title:[rs stringForColumn:@"title"] Body:[rs stringForColumn:@"body"] ]; [result addObject:tr]; [tr release]; } [rs close]; return result;}// INSERT-(void)insertWithTitle:(NSString *)title Body:(NSString *)body{ [db executeUpdate:[self setTable:@"INSERT INTO %@ (title, body) VALUES (?,?)"], title, body]; if ([db hadError]) { NSLog(@"Err %d: %@", [db lastErrorCode], [db lastErrorMessage]); }}// UPDATE-(BOOL)updateAt:(int)index Title:(NSString *)title Body:(NSString *)body{ BOOL success = YES; [db executeUpdate:[self setTable:@"UPDATE %@ SET title=?, body=? WHERE id=?"], title, body, [NSNumber numberWithInt:index]]; if ([db hadError]) { NSLog(@"Err %d: %@", [db lastErrorCode], [db lastErrorMessage]); success = NO; } return success;}// DELETE- (BOOL)deleteAt:(int)index{ BOOL success = YES; [db executeUpdate:[self setTable:@"DELETE FROM %@ WHERE id = ?"], [NSNumber numberWithInt:index]]; if ([db hadError]) { NSLog(@"Err %d: %@", [db lastErrorCode], [db lastErrorMessage]); success = NO; } return success;}- (void)dealloc { [super dealloc];}@end |
爲了確認程序正確，添加一個 UITableView。使用 initWithNibName 測試 DAO。
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//NoteController.h#import <UIKit/UIKit.h>@class TbNoteDao;@interface NoteController : UIViewController <UITableViewDataSource, UITableViewDelegate>{ UITableView *myTableView; TbNoteDao *tbNoteDao; NSMutableArray *record;}@property (nonatomic, retain) UITableView *myTableView;@property (nonatomic, retain) TbNoteDao *tbNoteDao;@property (nonatomic, retain) NSMutableArray *record;@end//NoteController.m#import "NoteController.h"#import "TbNoteDao.h"#import "TbNote.h"@implementation NoteController@synthesize myTableView, tbNoteDao, record;- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil { if (self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]) { tbNoteDao = [[TbNoteDao alloc] init]; [tbNoteDao insertWithTitle:@"TEST TITLE" Body:@"TEST BODY"];// [tbNoteDao updateAt:1 Title:@"UPDATE TEST" Body:@"UPDATE BODY"];// [tbNoteDao deleteAt:1]; record = [[tbNoteDao select] retain]; } return self;}- (void)viewDidLoad { [super viewDidLoad]; myTableView = [[UITableView alloc] initWithFrame:[[UIScreen mainScreen] applicationFrame]]; myTableView.delegate = self; myTableView.dataSource = self; self.view = myTableView;}- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return 1;}- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return [record count];}- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:CellIdentifier] autorelease]; } TbNote *tr = (TbNote *)[record objectAtIndex:indexPath.row]; cell.text = [NSString stringWithFormat:@"%i %@", [tr getIndex], tr.title]; return cell;}- (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning];}- (void)dealloc { [super dealloc];}@end |
最後開看看連接DB，和添加 ViewController 的處理。這一同樣不使用 Interface Builder。
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//SqlSampleAppDelegate.h#import <UIKit/UIKit.h>@class FMDatabase;@interface SqlSampleAppDelegate : NSObject <UIApplicationDelegate> { UIWindow *window; FMDatabase *db;}@property (nonatomic, retain) IBOutlet UIWindow *window;@property (nonatomic, retain) FMDatabase *db;- (BOOL)initDatabase;- (void)closeDatabase;@end//SqlSampleAppDelegate.m#import "SqlSampleAppDelegate.h"#import "FMDatabase.h"#import "FMDatabaseAdditions.h"#import "NoteController.h"@implementation SqlSampleAppDelegate@synthesize window;@synthesize db;- (void)applicationDidFinishLaunching:(UIApplication *)application { if (![self initDatabase]){ NSLog(@"Failed to init Database."); } NoteController *ctrl = [[NoteController alloc] initWithNibName:nil bundle:nil]; [window addSubview:ctrl.view]; [window makeKeyAndVisible];}- (BOOL)initDatabase{ BOOL success; NSError *error; NSFileManager *fm = [NSFileManager defaultManager]; NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString *documentsDirectory = [paths objectAtIndex:0]; NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:@"sample.db"]; success = [fm fileExistsAtPath:writableDBPath]; if(!success){ NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"sample.db"]; success = [fm copyItemAtPath:defaultDBPath toPath:writableDBPath error:&error]; if(!success){ NSLog([error localizedDescription]); } success = NO; } if(success){ db = [[FMDatabase databaseWithPath:writableDBPath] retain]; if ([db open]) { [db setShouldCacheStatements:YES]; }else{ NSLog(@"Failed to open database."); success = NO; } } return success;}- (void) closeDatabase{ [db close];}- (void)dealloc { [db release]; [window release]; [super dealloc];}@end |