定義
FMDB是iOS平臺的SQLite數據庫框架
FMDB以OC的方式封裝了SQLite得C語言API
優點
1.使用起來更加面向對象,省去了很多麻煩、冗餘的C語言代碼
2.對比蘋果自帶的Core Data框架,更加輕量級和靈活
3.提供了多線程安全的數據庫操作方法,有效地防止數據混亂
FMDB有三個主要的類
(1)FMDatabase
一個FMDatabase對象就代表一個單獨的SQLite數據庫
用來執行SQL語句
(2)FMResultSet
使用FMDatabase執行查詢後的結果集
(3)FMDatabaseQueue
用於在多線程中執行多個查詢或更新,它是線程安全的
通過指定SQLite數據庫文件路徑來創建FMDatabase對象
FMDatabase *db = [FMDatabase databaseWithPath:path];
if (![db open]) {
NSLog(@"數據庫打開失敗!");
}
文件路徑有三種情況
(1)具體文件路徑
如果不存在會自動創建
(2)空字符串@""
會在臨時目錄創建一個空的數據庫
當FMDatabase連接關閉時,數據庫文件也被刪除
(3)nil
會創建一個內存中臨時數據庫,當FMDatabase連接關閉時,數據庫會被銷燬
//
// ViewController.m
// FMDB_DataBase
//
// Created by lanou3g on 15-3-7.
// Copyright (c) 2015年 lanou3g. All rights reserved.
//
#import "ViewController.h"
#import "FMDatabase.h"
@interface ViewController ()
//數據庫
@property(nonatomic,retain)FMDatabase *db;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
//
// //獲得數據庫文件的路徑
// NSString *fileName = [NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
//
// //獲得數據庫
// FMDatabase *db = [FMDatabase databaseWithPath:fileName];
//
// //打開數據庫
// BOOL open = [db open];
////
//// BOOL close = [db close];
////
//// if (close) {
////
//// NSLog(@"關閉數據庫成功");
//// }else{
////
//// NSLog(@"關閉數據庫失敗");
////
//// }
//
// //打開數據庫
// if (open) {
//
// NSLog(@"ss");
//
// }else{
//
// NSLog(@"dd");
// }
//
// //創建表
// if (open) {
//
// BOOL result = [db executeUpdate:@"CREATE TABLE IF NOT EXISTS t_student (id integer PRIMARY KEY AUTOINCREMENT, name text NOT NULL, age integer NOT NULL)"];
//
// if (result) {
//
// NSLog(@"創建表成功");
//
// }else{
//
// NSLog(@"創建表失敗");
//
// }
// }
//
// self.db = db;
//
//1.獲得數據庫文件的路徑
NSString *doc=[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject];
NSString *fileName=[doc stringByAppendingPathComponent:@"student.sqlite"];
//2.獲得數據庫
FMDatabase *db=[FMDatabase databaseWithPath:fileName];
//3.打開數據庫
if ([db open]) {
//4.創表
BOOL result=[db executeUpdate:@"CREATE TABLE IF NOT EXISTS t_student (id integer PRIMARY KEY AUTOINCREMENT, name text NOT NULL, age integer NOT NULL);"];
if (result) {
NSLog(@"創表成功");
}else
{
NSLog(@"創表失敗");
}
}
self.db=db;
}
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
// //[self delete];
// [self insert];
[self query];
}
//插入數據
-(void)insert
{
for (int i = 0; i<10; i++) {
NSString *name = [NSString stringWithFormat:@"jack-%d", arc4random_uniform(100)];
// executeUpdate : 不確定的參數用?來佔位
BOOL result = [self.db executeUpdate:@"INSERT INTO t_student (name, age) VALUES (?, ?);", name, @(arc4random_uniform(40))];
if (result) {
NSLog(@"插入數據成功");
}else{
NSLog(@"插入數據失敗");
}
// [self.db executeUpdate:@"INSERT INTO t_student (name, age) VALUES (?, ?);" withArgumentsInArray:@[name, @(arc4random_uniform(40))]];
// executeUpdateWithFormat : 不確定的參數用%@、%d等來佔位
// [self.db executeUpdateWithFormat:@"INSERT INTO t_student (name, age) VALUES (%@, %d);", name, arc4random_uniform(40)];
}
}
//刪除數據
-(void)delete {
BOOL result = [self.db executeUpdate:@"DELETE FROM t_student;"];
if (result) {
NSLog(@"刪除數據成功");
}else{
NSLog(@"刪除數據失敗");
}
// [self.db executeUpdate:@"DROP TABLE IF EXISTS t_student;"];
// [self.db executeUpdate:@"CREATE TABLE IF NOT EXISTS t_student (id integer PRIMARY KEY AUTOINCREMENT, name text NOT NULL, age integer NOT NULL);"];
}
//查詢
- (void)query
{
// 1.執行查詢語句
FMResultSet *resultSet = [self.db executeQuery:@"SELECT * FROM t_student"];
// 2.遍歷結果
while ([resultSet next]) {
int ID = [resultSet intForColumn:@"id"];
NSString *name = [resultSet stringForColumn:@"name"];
int age = [resultSet intForColumn:@"age"];
NSLog(@"%d %@ %d", ID, name, age);
}
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end