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", @, @"女"] && isSucced;
         isSucced = [db executeUpdate:@"insert into t_student (name, age, sex) values (?, ?, ?)", @"石兰", @, @"女"] && isSucced;
         isSucced = [db executeUpdate:@"insert into t_student (name, age, sex) values (?, ?, ?)", @"卫庄", @, @"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;
 }