第九节用SQLite管理数据库(2)

@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
创建DAO（Data Access Objects）
这里将FMDB 的函数调用封装为DAO 的方式。

//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 取得打开的数据库
    SqlSampleAppDelegate *appDelegate = (SqlSampleAppDelegate *)[[UIApplication sharedApplication] delegate];
    db = [[appDelegate db] retain];
}
return self;
}
// 子类中实现
-(NSString *)setTable:(NSString *)sql{
return NULL;
}

- (void)dealloc {
[db release];
[super dealloc];
}

@end
下面是访问TbNote 表格的类。
//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]);

课程关键词:

第九节 用SQLite管理数据库(2)

第九节用SQLite管理数据库(2)