ios简单数据库运用

一.添加类

二.打开数据库

三.创表

四.插入数据

五.取出数据

一.添加类

1.在设置Linked Frameworks and Libraries 中，点加号并添加libsqlite3.0.dylib.

2.在控制器.m文件中，添加头文件#import<sqlite3.h>

二.打开数据库

sqlite3 *db = NULL;//创建数据库对象实例

int status = sqlite3_open(filename.UTF8String, &db);//打开数据库，返回的是bool类型。记得将OC转为c语言

三.创表

//squlite3_exec(sqlite3 *, const char *sql,int(*callback)(void *,int,char **),void *，char **errmsg);//一般用在没有返回值

const char *sql = "CREATE TABLE IF NOT EXISTS t_shop (id integer PRIMARY KEY, name text NOT NULL, price real);";

char *errmsg = NULL;

sqlite3_exec(self.db, sql, NULL, NULL, &errmsg);

四.插入数据

NSString *sql = [NSString stringWithFormat:@"INSERT INTO t_shop(name, price) VALUES ('%@', %f);", self.nameField.text, self.priceField.text.doubleValue]; sqlite3_exec(self.db, sql.UTF8String, NULL, NULL, NULL); // 刷新表格

五.取出数据

NSString *sql = [NSString stringWithFormat:@"SELECT name,price FROM t_shop WHERE name LIKE '%%%@%%' OR price LIKE '%%%@%%' ;", searchText, searchText];

// stmt是用来取出查询结果的

sqlite3_stmt *stmt = NULL;

    // 准备
    int status = sqlite3_prepare_v2(self.db, sql.UTF8String, -1, &stmt, NULL);
    if (status == SQLITE_OK) { // 准备成功 -- SQL语句正确
        while (sqlite3_step(stmt) == SQLITE_ROW) { // 成功取出一条数据
            const char *name = (const char *)sqlite3_column_text(stmt, 0);
            const char *price = (const char *)sqlite3_column_text(stmt, 1);

            HMShop *shop = [[HMShop alloc] init];
            shop.name = [NSString stringWithUTF8String:name];
            shop.price = [NSString stringWithUTF8String:price];
            [self.shops addObject:shop];
        }
    }

    [self.tableView reloadData];

六.模糊查询

a.增加搜索框
b.设置代理<UISearchBarDelegate>
   searchBar.delegeta = self;
c.实现- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText
D.数据库语句NSString *sql = [NSString stringWithFormat:@"SELECT name,price FROM t_shop WHERE name LIKE '%%%@%%' OR price LIKE '%%%@%%' ;", searchText, searchText];

代码：

#import "HMViewController.h"
#import <sqlite3.h>
#import "HMShop.h"

@interface HMViewController () <UITableViewDataSource, UISearchBarDelegate>
@property (weak, nonatomic) IBOutlet UITextField *nameField;
@property (weak, nonatomic) IBOutlet UITextField *priceField;
/** 数据库对象实例 */
@property (nonatomic, assign) sqlite3 *db;
@property (weak, nonatomic) IBOutlet UITableView *tableView;
- (IBAction)insert;
@property (nonatomic, strong) NSMutableArray *shops;
@end

@implementation HMViewController

- (NSMutableArray *)shops
{
    if (!_shops) {
        self.shops = [[NSMutableArray alloc] init];
    }
    return _shops;
}

- (void)viewDidLoad
{
    [super viewDidLoad];

    // 增加搜索框
    UISearchBar *searchBar = [[UISearchBar alloc] init];
    searchBar.frame = CGRectMake(0, 0, 320, 44);
    searchBar.delegate = self;
    self.tableView.tableHeaderView = searchBar;

    // 初始化数据库
    [self setupDb];

    // 查询数据
    [self setupData];

    // 关闭数据库
    //    sqlite3_close();
}

#pragma mark - UISearchBarDelegate
- (void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText
{
    [self.shops removeAllObjects];

    NSString *sql = [NSString stringWithFormat:@"SELECT name,price FROM t_shop WHERE name LIKE '%%%@%%' OR  price LIKE '%%%@%%' ;", searchText, searchText];
    // stmt是用来取出查询结果的
    sqlite3_stmt *stmt = NULL;
    // 准备
    int status = sqlite3_prepare_v2(self.db, sql.UTF8String, -1, &stmt, NULL);
    if (status == SQLITE_OK) { // 准备成功 -- SQL语句正确
        while (sqlite3_step(stmt) == SQLITE_ROW) { // 成功取出一条数据
            const char *name = (const char *)sqlite3_column_text(stmt, 0);
            const char *price = (const char *)sqlite3_column_text(stmt, 1);

            HMShop *shop = [[HMShop alloc] init];
            shop.name = [NSString stringWithUTF8String:name];
            shop.price = [NSString stringWithUTF8String:price];
            [self.shops addObject:shop];
        }
    }

    [self.tableView reloadData];
}

/**
 查询数据
 */
- (void)setupData
{
    const char *sql = "SELECT name,price FROM t_shop;";
    // stmt是用来取出查询结果的
    sqlite3_stmt *stmt = NULL;
    // 准备
    int status = sqlite3_prepare_v2(self.db, sql, -1, &stmt, NULL);
    if (status == SQLITE_OK) { // 准备成功 -- SQL语句正确
        while (sqlite3_step(stmt) == SQLITE_ROW) { // 成功取出一条数据
            const char *name = (const char *)sqlite3_column_text(stmt, 0);
            const char *price = (const char *)sqlite3_column_text(stmt, 1);

            HMShop *shop = [[HMShop alloc] init];
            shop.name = [NSString stringWithUTF8String:name];
            shop.price = [NSString stringWithUTF8String:price];
            [self.shops addObject:shop];
        }
    }
}

/**
 初始化数据库
 */
- (void)setupDb
{
    // 打开数据库(连接数据库)
    NSString *filename = [[NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES) lastObject] stringByAppendingPathComponent:@"shops.sqlite"];
    // 如果数据库文件不存在, 系统会自动创建文件自动初始化数据库
    int status = sqlite3_open(filename.UTF8String, &_db);
    if (status == SQLITE_OK) { // 打开成功
        NSLog(@"打开数据库成功");

        // 创表
        const char *sql = "CREATE TABLE IF NOT EXISTS t_shop (id integer PRIMARY KEY, name text NOT NULL, price real);";
        char *errmsg = NULL;
        sqlite3_exec(self.db, sql, NULL, NULL, &errmsg);
        if (errmsg) {
            NSLog(@"创表失败--%s", errmsg);
        }
    } else { // 打开失败
        NSLog(@"打开数据库失败");
    }
}

- (IBAction)insert {
    NSString *sql = [NSString stringWithFormat:@"INSERT INTO t_shop(name, price) VALUES ('%@', %f);", self.nameField.text, self.priceField.text.doubleValue];
    sqlite3_exec(self.db, sql.UTF8String, NULL, NULL, NULL);

    // 刷新表格
    HMShop *shop = [[HMShop alloc] init];
    shop.name = self.nameField.text;
    shop.price = self.priceField.text;
    [self.shops addObject:shop];
    [self.tableView reloadData];
}

#pragma mark - 数据源方法
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return self.shops.count;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *ID = @"shop";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:ID];
    if (!cell) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:ID];
        cell.backgroundColor = [UIColor grayColor];
    }

    HMShop *shop = self.shops[indexPath.row];
    cell.textLabel.text = shop.name;
    cell.detailTextLabel.text = shop.price;

    return cell;
}
@end