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。
原文地址：http://blog.csdn.net/wq820203420/article/details/46288993
