iOS FMDB自己封装的单例类

//
//  DataBaseHelper.h
//  FMDB
//
//  Created by 王聪 on 14/8/25.
//  Copyright (c) 2014年 Congwang. All rights reserved.
//

#import
#import "FMDatabase.h"
@interface DataBaseHelper : NSObject
+ (DataBaseHelper *)sharedDataBaseHelper;
@property (nonatomic, strong) FMDatabase *db;
@end


//
//  DataBaseHelper.m
//  FMDB
//
//  Created by wangcong on 15/8/25.
//  Copyright (c) 2015年 Congwang. All rights reserved.
//

#import "DataBaseHelper.h"
#import "Contact.h"
static DataBaseHelper*helper = nil;
@implementation DataBaseHelper
+ (DataBaseHelper *)sharedDataBaseHelper{
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        helper = [[DataBaseHelper alloc] init];
        [helper createDataBase];
        [helper createTable];
    });return helper;
}
//创建数据库
- (void)createDataBase{
    NSString *doc = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)firstObject];
    NSString *filePath = [doc stringByAppendingPathComponent:@"contacts.sqlite"];
    //创建数据库
    self.db = [FMDatabase databaseWithPath:filePath];
}
//创建表
- (void)createTable{
    if ([self.db open]) {
        BOOL result = [self.db executeUpdate:@"CREATE TABLE IF NOT EXISTS t_contact (id integer PRIMARY KEY AUTOINCREMENT, name text NOT NULL, phoneNum text NOT NULL);"];
        if (result) {
            NSLog(@"创建成功");
        }else{
            NSLog(@"创建失败");
        }[self.db close];
    }else{
        NSLog(@"数据库打开失败");
    }
}
//插入操作
- (void)insertContact:(Contact *)contact{
    if ([self.db open]) {
        BOOL result = [self.db executeUpdate:@"INSERT INTO t_contact (name, phoneNum) VALUES (?,?);", contact.name, contact.phoneNum];
        if (result) {
            NSLog(@"创建成功");
        }else{
            NSLog(@"创建失败");
        }
        [self.db close];
    }else{
        NSLog(@"数据库打开失败");
    }
}
//删除
- (void)deleteContact:(Contact *)contact{
    if ([self.db open]) {
        BOOL result = [self.db executeUpdate:@"delete from t_contact where phoneNum = ?",contact.phoneNum];
        if (result) {
            NSLog(@"创建成功");
        }else{
            NSLog(@"创建失败");
        }
        [self.db close];
    }else{
        NSLog(@"数据库打开失败");
    }
}
//修改数据
- (void)updateContact:(Contact *)contact
{
    if ([self.db open]) {
        BOOL result = [self.db executeUpdate:@"UPDATE t_contact SET name = ?,phoneNum = ? WHERE phoneNum = ?",
                       contact.name,contact.phoneNum,contact.phoneNum];
        if (result) {
            NSLog(@"修改成功");
        }
        else
        {
            NSLog(@"修改失败");
        } [self.db close];
    }else{
        NSLog(@"数据库打开失败");
    }
}
//查询
- (NSArray *)queryContact{
    NSMutableArray *arr = [NSMutableArray array];
    if ([self.db open]) {
        FMResultSet *set = [self.db executeQuery:@"SELECT * FROM t_contact"];
        while ([set next]) {
            NSInteger ID = [set intForColumn:@"id"];
            NSString *name = [set stringForColumn:@"name"];
            NSString *phoneNum = [set stringForColumn:@"phoneNum"];
            Contact *contact = [[Contact alloc] initWithName:name phoneNum:phoneNum];
            [arr addObject:contact];
        }
    }
    return arr;
}



@end