iOS 之数据库

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建立一个类文件，在.h文件里写入几个属性

#import <Foundation/Foundation.h>

@interface Person : NSObject

@property (nonatomic, assign)NSInteger number;

@property (nonatomic, copy)NSString *name;

@property (nonatomic, copy)NSString *gender;

@property (nonatomic, assign)NSInteger age;

@end

再建立一个类文件，在.h文件里声明几个需要数据库使用的方法

#import <Foundation/Foundation.h>

#import "Person.h"

#warning第一步引入sqlite3.h 数据库头文件

#import <sqlite3.h>

@interface MyModel : NSObject

+ (instancetype)sharePerson;

- (void)openDB;

- (void)insertStudent:(Person *)person;

- (void)updateStudent:(Person *)person number:(NSInteger)number;

- (void)deleStudent:(NSInteger)number;

- (NSMutableArray *)selectAllStudent;

@end

在.m文件里写入声明的方法

#import "MyModel.h"

@implementation MyModel

+ (instancetype)sharePerson

{

static MyModel *model = nil;

if (model == nil) {

model = [[MyModel alloc]init];

}

return model;

}

#warning第二步加入libsqlite3.0 库文件

#warning第三步创建数据库对象

static sqlite3 *db = nil;

#warning第四步打开数据库

- (void)openDB

{

if (db != nil) {

NSLog(@"数据库已经打开");

return;

}

NSArray *array = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

NSString *path = [array lastObject];

NSString *sqlitePath = [path stringByAppendingPathComponent:@"student.sqlite"];

NSLog(@"sqlitePath == %@", sqlitePath);

//打开数据库

int result = sqlite3_open(sqlitePath.UTF8String, &db);

if (result == SQLITE_OK) {

NSLog(@"数据库打开成功");

//数据库建表

NSString *createSql = @"CREATE TABLE IF NOT EXISTS lanou23(number INTEGER PRIMARY KEY AUTOINCREMENT, name TEXT, gender TEXT, age, INTEGER)";

int RESULT = sqlite3_exec(db, createSql.UTF8String, NULL, NULL, nil);

if (RESULT == SQLITE_OK) {

NSLog(@"创建表成功");

}else

{

NSLog(@"创建表失败");

}

else

{

NSLog(@"数据库打开失败");

}

#warning第五步插入数据

- (void)insertStudent:(Person *)person

{

//创建插入语句

NSString *insertSql = [NSString stringWithFormat:@"INSERT INTO lanou23(name, gender, age) values('%@', '%@', '%ld')", person.name, person.gender, person.age];

int RESULT = sqlite3_exec(db, insertSql.UTF8String, NULL, NULL, nil);

if (RESULT == SQLITE_OK) {

NSLog(@"插入成功");

}else

{

NSLog(@"插入失败");

}

#warning第六步修改

- (void)updateStudent:(Person *)person number:(NSInteger)number

{

NSString *updateSql = [NSString stringWithFormat:@"UPDATE lanou23 SET name = '%@', gender = '%@', age = '%ld' WHERE number = '%ld'",person.name, person.gender, person.age ,number];

int result = sqlite3_exec(db, updateSql.UTF8String, NULL, NULL, nil);

if (result == SQLITE_OK) {

NSLog(@"修改成功");

}else

{

NSLog(@"修改失败");

}

#warning第七步删除

- (void)deleStudent:(NSInteger)number

{

NSString *deleSql = [NSString stringWithFormat:@"DELETE FROM lanou23 WHERE number = '%ld'", number];

int result = sqlite3_exec(db, deleSql.UTF8String, NULL, NULL, nil);

if (result == SQLITE_OK) {

NSLog(@"删除成功");

}else

{

NSLog(@"删除失败");

}

#warning第八步查询所有学生

- (NSMutableArray *)selectAllStudent

{

NSMutableArray *array = [NSMutableArray array];

NSString *selectSql = @"SELECT * FROM lanou23";//查询所有

// NSString *selectSql = [NSString stringWithFormat:@"SELECT * FROM lanou23 WHERE name = '%@'", @"123"];//查询某一个

//声明数据库跟随指针,作用是跟踪表里的每一行

sqlite3_stmt *stmt = nil;

//查询之前准备工作:将数据库对象db,sql语句.stmt关联起来

//参数1.数据库对象

//参数2.sql语句

//参数3.sql语句长度,-1为不限制长度

//参数4.数据库跟随指针

int result = sqlite3_prepare_v2(db, selectSql.UTF8String, -1, &stmt, nil);

if (result == SQLITE_OK) {

NSLog(@"查询成功");

//循环遍历每一条数据

while (sqlite3_step(stmt) == SQLITE_ROW) {

//取值, 1为name下标

const unsigned char * name = sqlite3_column_text(stmt, 1);

const unsigned char * gender = sqlite3_column_text(stmt, 2);

int number = sqlite3_column_int(stmt, 0);

int age = sqlite3_column_int(stmt, 3);

NSString *nameStr = [NSString stringWithUTF8String:(const char *)name];

NSString *genderStr = [NSString stringWithUTF8String:(const char *)gender];

NSInteger numberInteger = number;

NSInteger ageInteger = age;

Person *pp = [[Person alloc]init];

pp.name = nameStr;

pp.gender = genderStr;

pp.age = ageInteger;

pp.number = numberInteger;

[array addObject:pp];

}

}else

{

NSLog(@"查询失败");

}

return array;

}

#pragma mark关闭数据库

- (void)closeDB

{

// 1.关闭数据库

int result = sqlite3_close(db);

// 2.判断是否关闭成功

if (result == SQLITE_OK) {

NSLog(@"关闭成功");

#warning关闭成功后，把数据库对象置为nil

db = nil;

} else {

NSLog(@"关闭失败");

}

@end

在需要调用数据库的页面.h文件里引入数据库的头文件及属性类的头文件

#import <UIKit/UIKit.h>

#import "Person.h"

#import "MyModel.h"

@interface RootViewController : UIViewController

@end

在需要调用数据库的页面.m文件里调用所需要使用的数据库文件方法

#import "RootViewController.h"

@interface RootViewController ()

@end

@implementation RootViewController

- (void)viewDidLoad {

[super viewDidLoad];

// Do any additional setup after loading the view.

self.view.backgroundColor = [UIColor cyanColor];

MyModel *model = [MyModel sharePerson];

[model openDB];

Person *pp = [[Person alloc]init];

pp.name = @"123";

pp.gender = @"男";

pp.age = 23;

[model insertStudent:pp];

Person *pp1 = [[Person alloc]init];

pp1.name = @"456";

pp1.gender = @"女";

pp1.age = 26;

[model updateStudent:pp1 number:1];

[model deleStudent:3];

self.array = [model selectAllStudent];

for (Person *ppp in self.array) {

NSLog(@"ppp.name ===== %@", ppp.name);

}

- (void)didReceiveMemoryWarning {

[super didReceiveMemoryWarning];

// Dispose of any resources that can be recreated.

}

#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation

- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {

// Get the new view controller using [segue destinationViewController].

// Pass the selected object to the new view controller.

}

@end

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iOS 之 数据库

iOS 之数据库