ios FMDB初体验之增删改查

来源：互联网发布：银光软件编辑：程序博客网时间：2024/06/15 23:20
又又好久没见了。想你们。今天写一篇关于fmdb的使用文章。在工作中，我们有时会用到数据库，所以你会需要一个好用的工具。长话短说开始进入正题。
先导入fmdb库文件。还有就是加入libsqlite3.dylib。这2个前期准备好后，我们就可以开工了。
#import "ViewController.h"#import "FMDB.h"  //导入头文件@interface ViewController ()@property(nonatomic,retain) FMDatabaseQueue *fmQueue;//添加一个队列属性@end@implementation ViewController//你数据库的路径-(FMDatabaseQueue *)fmQueue{            if (_fmQueue== nil) {        NSString *dbPath = [NSHomeDirectory() stringByAppendingPathComponent:@"Documents/student.sqlite"];                _fmQueue = [FMDatabaseQueue databaseQueueWithPath:dbPath];                NSLog(@"%@",dbPath);    }        return _fmQueue;    }- (void)viewDidLoad {    [super viewDidLoad];      [self createAllBtn];        //这是在一个代码块中    [self.fmQueue inDatabase:^(FMDatabase *db) {            //创建一个表     [db executeUpdate:@"create table if not exists t_student (id integer primary key autoincrement, name text not null, age integer)"];        //保持数据库开启        if (![db open]) {                        return ;        }    }];    }-(void)createAllBtn{            UIButton *btn = [UIButton buttonWithType:UIButtonTypeSystem];        btn.frame = CGRectMake(100, 50, 100, 50);    [btn setTitle:@"增加数据" forState:UIControlStateNormal];        [btn setTitleColor:[UIColor redColor] forState:UIControlStateNormal];    [btn addTarget:self action:@selector(increaseAction:) forControlEvents:UIControlEventTouchUpInside];    [self.view addSubview:btn];                UIButton *btn1 = [UIButton buttonWithType:UIButtonTypeSystem];        btn1.frame = CGRectMake(100, 100, 100, 50);    [btn1 setTitle:@"删除数据" forState:UIControlStateNormal];        [btn1 setTitleColor:[UIColor redColor] forState:UIControlStateNormal];    [btn1 addTarget:self action:@selector(deleteAction:) forControlEvents:UIControlEventTouchUpInside];    [self.view addSubview:btn1];                    UIButton *btn2 = [UIButton buttonWithType:UIButtonTypeSystem];        btn2.frame = CGRectMake(100, 150, 100, 50);    [btn2 setTitle:@"修改数据" forState:UIControlStateNormal];        [btn2 setTitleColor:[UIColor redColor] forState:UIControlStateNormal];    [btn2 addTarget:self action:@selector(modifyAction:) forControlEvents:UIControlEventTouchUpInside];    [self.view addSubview:btn2];                    UIButton *btn3 = [UIButton buttonWithType:UIButtonTypeSystem];        btn3.frame = CGRectMake(100, 200, 100, 50);    [btn3 setTitle:@"查询数据" forState:UIControlStateNormal];        [btn3 setTitleColor:[UIColor redColor] forState:UIControlStateNormal];    [btn3 addTarget:self action:@selector(searchAction:) forControlEvents:UIControlEventTouchUpInside];    [self.view addSubview:btn3];    }-(void)increaseAction:(UIButton *)btn{        NSLog(@"增加数据");            [self.fmQueue inDatabase:^(FMDatabase *db) {               for (int i = 0; i<100; i++) {                                    NSString *name = [NSString stringWithFormat:@"james"];                        int age = 10;                                                [db executeUpdate:@"insert into t_student (name,age) values (?,?)",name,[NSNumber numberWithInt:age]];                    }                    }];    }-(void)deleteAction:(UIButton *)btn{        NSLog(@"删除数据");        [self.fmQueue inDatabase:^(FMDatabase *db) {                NSString *name = [NSString stringWithFormat:@"james"];                //注意下这样是不能删除指定数据的，一定要是字符串nsstring类型        //[db executeUpdate:@"delete from t_student where name = '%@'",name];        //也就是这样        NSString *sql = [NSString stringWithFormat:@"delete from t_student where name = '%@'",name];        [db executeUpdate:sql];            }];        }-(void)modifyAction:(UIButton *)btn{        NSLog(@"修改数据");            [self.fmQueue inDatabase:^(FMDatabase *db) {        NSString *name = [NSString stringWithFormat:@"wq"];                NSString *set = [NSString stringWithFormat:@"UPDATE  t_student SET name = '%@'",name];        [db executeUpdate:set];            }];            }-(void)searchAction:(UIButton *)btn{        NSLog(@"查询数据");    [self.fmQueue inDatabase:^(FMDatabase *db) {               NSString *sql = [NSString stringWithFormat:@"SELECT *from t_student"];    FMResultSet *set = [db executeQuery:sql];        while ([set next])    {        int stuId = [set intForColumn:@"id"];        NSString *name = [set stringForColumn:@"name"];        int age = [set intForColumn:@"age"];                NSLog(@"stuId = %d, name = %@, age = %d", stuId, name, age);                //这里的textview用于显示查询到的数据        UITextView *text = [[UITextView alloc]init];        text.frame = CGRectMake(50, 300, 300, 200);        text.backgroundColor = [UIColor grayColor];                        [text setText:name];        [self.view addSubview:text];                 }            }];    }@end
没错就是这样，很简单，大家可以拉到工程中运行下。
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