ios数据存储（三）

/**
 数据库三个步骤：
 1，打开
 2，操作
 3，关闭
 */

#import "ViewController.h"
#import "FMDB.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

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

    NSString *path = [pathesArr firstObject];

    NSString *dbPath = [path stringByAppendingPathComponent:@"sqlite.db"];
    NSLog(@"%@",dbPath);


    //考虑了线程安全的问题
    FMDatabaseQueue *queue = [FMDatabaseQueue databaseQueueWithPath:dbPath];
    [queue inDatabase:^(FMDatabase *db) {

        FMResultSet *set = [db executeQuery:@"select id from myTable where name = 'wangbing';"];

        //遍历所得到的结果
        while ([set next]) {
            int int_id = [set intForColumn:@"id"];
            NSLog(@"%zi",int_id);
        }
        //结果集需要关闭
        [set close];
        [db close];
    }];

    //3，关闭
    [queue close];

}

//不考虑线程安全的方式来操作数据
- (void)dbByDatabase{
    NSArray *pathesArr =  NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

    NSString *path = [pathesArr firstObject];

    NSString *dbPath = [path stringByAppendingPathComponent:@"sqlite.db"];
    NSLog(@"%@",dbPath);

    //FMDatabase：数据库类
    FMDatabase *database = [FMDatabase databaseWithPath:dbPath];

    if ([database open]) {
        //2，操作

        //建表
        if ([database executeUpdate:@"create table if not exists 'myTable' (id int,name varchar(255),height float, primary key (id)) ;"]) {
            NSLog(@"建表成功");

            //插入数据
            //            if ([database executeUpdate:@"insert into myTable (id,name,height) values (1,'yhuihui',172);"]) {
            //                NSLog(@"插入数据成功");
            //            }

            /*
             //利用占位符的方式插入某条数据
             if ([database executeUpdate:@"insert into myTable (id,name,height) values (?,?,?);",[NSNumber numberWithInt:3],@"wangshuo",[NSNumber numberWithFloat:178.0f]]) {
             NSLog(@"插入数据成功");
             }
             */

            /*
             //删除数据
             if ([database executeUpdate:@"DELETE FROM myTable WHERE id = 1;"]) {
             NSLog(@"删除数据成功");
             }
             */

            /*
             if ([database executeUpdate:@"UPDATE myTable SET name = 'lixiujuan' WHERE id = 2;"]) {
             NSLog(@"更新数据成功");
             }
             */

            FMResultSet *set = [database executeQuery:@"select id from myTable where name = 'wangshuo';"];

            //遍历所得到的结果
            while ([set next]) {
                int int_id = [set intForColumn:@"id"];
                NSLog(@"%zi",int_id);
            }
            //结果集需要关闭
            [set close];
        };
    }

    //3，关闭
    [database close];
}