• 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
    
     
     
     
     
     
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  • 原文地址:https://www.cnblogs.com/zhongxuan/p/4792596.html
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