FMDB简单用法

首先引入类库

声明数据库和路径

/**  声明数据库对象  */

@property (nonatomic, strong) FMDatabase *dataBase;

 

/**  声明存储路径  */

@property (nonatomic, strong) NSString *filePath;

 

创建表：

#pragma mark - 创建表
- (void)createTable {
    
    // 1.创建sql语句
    NSString *str = @"create table if not exists t_student (id integer primary key autoincrement not null, name text not null, age integer not null, sex text not null)";
    
    // 2.找到存储路径
    NSString *document = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents"];
    self.filePath = [document stringByAppendingPathComponent:@"student.sqlite"];
    NSLog(@"filePath = %@", self.filePath);
    
    // 3.初始化FMDB对象
    self.dataBase = [FMDatabase databaseWithPath:self.filePath];
    
    // 4.判断数据库打开的时候才执行语句
    if ([self.dataBase open]) {
        BOOL result = [self.dataBase executeUpdate:str];
        
        if (result) {
            NSLog(@"创建表成功");
        } else {
            NSLog(@"创建表失败");
        }
    }
    
    // 5.关闭数据库
    [self.dataBase close];
}

添加

#pragma mark - 以队列方式插入多个学生【这种方式较为常用】
- (IBAction)insertManyStudent:(id)sender {
    
    // FMDB不支持多个线程同时操作，所以一般以串行的方式实现相关的操作
    
    // 1.打开数据库
    [self.dataBase open];
    
    // 2.创建操作队列
    FMDatabaseQueue *queue = [FMDatabaseQueue databaseQueueWithPath:self.filePath];
    
    // 3.标识：记录是否操作成功
    __block BOOL isSucced = YES;
    
    // 4.把所需要的事件打包放在操作队列中
    [queue inTransaction:^(FMDatabase *db, BOOL *rollback) {
        
        // 串行队列
        isSucced = [db executeUpdate:@"insert into t_student (name, age, sex) values (?, ?, ?)", @"高月", @10, @"女"] && isSucced;
        isSucced = [db executeUpdate:@"insert into t_student (name, age, sex) values (?, ?, ?)", @"石兰", @12, @"女"] && isSucced;
        isSucced = [db executeUpdate:@"insert into t_student (name, age, sex) values (?, ?, ?)", @"卫庄", @34, @"男"] && isSucced;
        
        // 如果有错误，就将它返回
        if (!isSucced) {
            // block返回的参数rollback进行处理(bool类型的指针)
            *rollback = YES;
            return;
        } else {
            NSLog(@"插入成功");
        }
    }];
    
    // 5.关闭数据库
    [self.dataBase close];
}

更改

#pragma mark - 更改学生
- (IBAction)updateAction:(id)sender {
    
    // 1.打开数据库
    [self.dataBase open];
    
    // 2.执行语句
    BOOL result = [self.dataBase executeUpdate:@"update t_student set name = ? where name = ?", @"少羽", @"卫庄"];
    if (result) {
        NSLog(@"更改成功");
    } else {
        NSLog(@"%d", result);
        NSLog(@"更改失败");
    }
    
    // 3.关闭数据库
    [self.dataBase close];
}

删除

#pragma mark - 删除学生
- (IBAction)deleteAction:(id)sender {
    
    // 1.打开数据库
    [self.dataBase open];
    
    // 2.执行sql语句
    BOOL result = [self.dataBase executeUpdate:@"delete from t_student where name = ?", @"少羽"];
    if (result) {
        NSLog(@"删除成功");
    } else {
        NSLog(@"删除失败");
    }
    
    // 3.关闭数据库
    [self.dataBase close];
}

查询所有

// 查询所有
- (NSMutableArray *)searchAll {
    
    [self.dataBase open];
    FMResultSet *resultSet = [self.dataBase executeQuery:@"select *from p_person"];
    NSMutableArray *array = [NSMutableArray array];
    while ([resultSet next]) {
        Person *person = [[Person alloc] init];
        person.id = [resultSet intForColumn:@"id"];
        person.name = [resultSet objectForColumnName:@"name"];
        person.age = [resultSet intForColumn:@"age"];
        person.weight = [resultSet doubleForColumn:@"weight"];
        
        [array addObject:person];
    }
    [self.dataBase close];
    return array;
}